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LIBRARY OF THE
UNIVERSITY OF ILLINOIS
AT URBANA-CHAMPAIGN

NOTICE: According to Sec. 19
(a) of the University Statutes,
all books and other library
materials acquired in any man-
ner by the University belong to
the University Library. When
this item is no longer needed
by the department, it should
be returned to the Acquisition
Department, University Library.

ILLINOIS NATURAL
HISTORY SURVEY

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At

ILLINOIS

Picidae \\

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Biological Notes No. 102

State of Illinois

ILLINOIS NATURAL HISTORY SURVEY Department of Registration and Eduéation
Urbana, Illinois — September, 1977 NATURAL HISTORY SURVEY DIVISION

ee

4 ; ‘
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Fig. 1.—Yellow-shafted flicker at a suet feeder in Urbana, Illinois. Black moustache marks indicate the bird is a male.

ILLINOIS BIRDS: Picidae

HIS IS THE SIXTH in a series of papers de-
BLE stened to summarize the extensive literature
n Illinois birds, with special emphasis on population
iology. The papers also include a large amount of
previously unpublished data from the authors’ contin-
uing field work, started in September 1956, plus data
contributed from numerous other observers over the
years, including field notes—some dating back into
the last century—from Benjamin T. Gault, Alfred O.
Gross, John J. Schafer, and Frank Smith and _ his
students.

The introductions to the other papers in the series,
beginning with the Mimidae (Graber et al. 1970), con-
tain statements of our procedures and policies to
which the reader of this paper should refer.

The present paper deals with the woodpeckers, of
which seven species occur regularly in Illinois in sub-
stantial numbers, one (the three-toed) occurs only
irregularly, one (Lewis’) is of accidental occurrence,
and one (the ivory-bill) is extirpated and possibly ex-
tinct. References to a ‘“‘white-headed woodpecker”’
(Musselman 1916 and 1916-1917) we assume refer
not to the western species of that name (Dendrocopos
albolarvatus) , but to an aberrantly plumaged bird of
some other species.

As we have examined the available information on
the woodpeckers and other species in recent years and
have observed, concommitantly, the accelerating dete-
rioration of natural habitats in Illinois, the need for
more precise knowledge of population-habitat rela-
tionships has become increasingly apparent. The am-
ple acreages of diverse habitats that supported about
400 species of Illinois birds into the twentieth century
are now being obliterated at an alarming rate. The
survival of even remnant populations of many of these
species will depend upon first understanding both the
qualitative and quantitative characteristics of the hab-
itat for each species and then preserving suitable habi-
tat areas of sufficient size wherever possible.

To help with the understanding of habitat-bird
population relationships, in June 1973 we inaugurated
annual studies of breeding and winter populations of
birds on several selected forest areas in southern Ili-
nois where we also studied the plant populations.
These studies of eight mature bottomland forests and
five upland forests have revealed some interesting cor-
relations between woodpecker population densities
and vegetational composition and structure, which are

This paper is published by authority of the State of Illinois, IRS Ch.
127, Par. 58.12. It is a contribution from the Section of Wildlife Research
of the Illinois Natural History Survey. Dr. Jean W. Graber and Dr.
Richard R. Graber are Wildlife Specialists and the late Miss Ethelyn L.
Kirk served as a Technical Assistant in the Section of Wildlife Research
at the Survey.

Jean W. Graber, Richard R. Graber, and Ethelyn L. Kirk

discussed under each species account. To insure ade-
quate census samples, we chose to study extensive for-
est tracts—each 300 acres or more in extent. No size-
able natural community is strictly homogeneous, and
each of our study areas includes a number of vegeta-
tional associations—old stands of several species of
trees intermingled in places with younger thickets
where old trees have fallen, opening the canopy to
sunlight for new growth. Considering the inherent
variability of each community and other variables,
such as weather, annual change, and observer alertness
that affect the populations and/or the census, it is per-
haps remarkable that statistically significant correla-
tions between bird populations and vegetation char-
acteristics were detected. Although all study areas
had certain characteristics in common, each was also
unique, providing us with a spectrum of forest types
with which to compare bird populations.

We arbitrarily divided bottomland from upland
forest on the basis of topography, including flatland
forest of the floodplain and the first level above as
bottomland and all else as upland. Certain consistent
vegetational changes also marked the two types. The
vegetation studies, made primarily in late summer and
fall, 1974-1975, were censuses of plants in two types of
circular quadrats—(1) 1/20th-acre quadrats in which
all woody stems were identified and counted and their
diameters (DBH) were measured and in which herba-
ceous ground cover was estimated as to percentage of
ground covered and (2) 1/10th-acre quadrats in which
only stems 4 inches or larger were counted and mea-
sured. The two types of plant quadrats were censused
alternately at regular intervals of 550 feet within our
census transect for birds, making the coverage about
one vegetation quadrat per acre of forest censused for
birds.

These parameters were examined for correlations
between numbers of woodpeckers of each species and
the woody vegetation: (1) Importance (Y) of each
genus and species of woody plant. Importance is cal-
culated from relative frequency, relative density, and
relative basal area (Lindsey et al. 1958), and each of
these factors was also examined separately for correla-
tions with the bird populations. (2) Size of woody
vegetation. Trees, living and dead, were classified as
small (4-10 inches DBH), medium (10-22 inches
DBH), or large (over 22 inches DBH). DBH (diam-
eter breast high) was measured in inches at approx-
imately 4.5 feet above the ground level. Woody plants
of the understory were divided into three size classes
(less than 1 inch, 1-2 inches, and 2-4 inches DBH).

3

(3) Total basal area (BA) and the ratio of the BA of
each size category of woody plants to the total BA of
all woody plants. Scientific names of most plants can
be found in Table 14. Names of plants not found in
Table 14 are given as they occur in the text.

The bottomland forest areas we censused (with the
letter designations used in Fig. 13, 22, and 36) were:
A—Beall Woods (Wabash County) ; B—Jim’s Pond,
2 miles southwest of New Memphis Station (St. Clair
County) ; C—Horseshoe Lake Nature Preserve (Alex-
ander County) ; D—Union County Wildlife Refuge;
E—Campbell Lake, 2 miles south-southeast of Old
Duquoin (Jackson County) ; F—Saline (Middlefork)
River, 2 miles north-northwest of Dorris Heights (Sa-
line County); G—Heron Pond Nature Preserve
(Johnson County); and H—Snider (Snyder) Lake,
3 miles east of Elkville (Jackson County). The upland
forest areas we censured were the upland parts of
Beall Woods and Heron Pond Nature Preserves; Pine
Hills, 3 miles N of Wolf Lake (Union County) ; Pos-
som Trot Trail, 2 miles SW of Elco (Alexander
County) ; and Kaskaskia Experimental Forest, 3 miles
SSW of Karbers Ridge (Hardin County) .

Though still too meager, there are relatively more
population figures for the Picidae than for most
groups, and certain points should be made here con-
cerning the tables that summarize these data. For the
sake of completeness we have included virtually all
published measurements of Illinois woodpecker pop-
ulations. However, it is obvious that census data for
small tracts—especially areas under 30 acres—may be
badly distorted because of the relatively large amount
of edge and the reduced possibility that the less com-
mon species of a fauna may be represented (Graber &
Graber 1976). The reader should, therefore, use dis-
cretion in accepting the population figures presented
for small areas. Also, because in most cases some inter-
pretation is required in abstracting population figures
from publications, we recommend that the reader refer
to the original sources if possible. In the population
tables where we have referred to the range of densities
in a long series of censuses, most notably those of S. C.
Kendeigh and his students, we have cited only the
papers that show the extremes of the population
range. Space limitations make it impossible to list all
of the papers in the series. The range of population
densities given for our recent (1973-1976) strip cen-
suses is not the range for annual variation, but the
range for different forest tracts, in each of which we
censused at least 40 acres.

These journals were sources of Christmas-count
data: Bird-Lore 1901-1940, Audubon Magazine 1941-
1946, Audubon Field Notes 1947-1970, American
Birds 1971-1976, and Audubon Bulletin 1932-1975.
Since the counts are made in late December and early
January of the following year, the year given in figures
and tables refers to the year represented by January.

4

We have included scientific names, excepting no-
menclature from other papers cited, and bird names
in general, for which we follow American Ornithol-
ogists’ Union checklist (1957) and supplements prior
to 1976.

As always, we are indebted to a number of people
for help, particularly for contributions of data and
opportunities to examine bird specimens and use data
from several scientific collections. We would partic-
ularly like to mention Frank Bellrose and Robert
Crompton of the Illinois Natural History Survey; S.
Charles Kendeigh of the University of Illinois; Mar-
ilyn Campbell, Gary L. Wilford, and Robert J. Schifo
of the Vermilion County Conservation District (Forest
Glen) ; Charles T. Clark of Des Plaines; Maurice Reed
and Jack Keegan of Dixon; Bowie Hannah of Dix;
William S. Brenneman of the Illinois Power Com-
pany; H. David Bohlen and Tim Cashatt of the Illi-
nois State Museum; Vernon Kleen of the Illinois De-
partment of Conservation; William B. Ahern and
Merril McHenry of Greenville College; John Wana-
maker of Principia College; L. Barrie Hunt of Eastern
Illinois University; Donald F. Hoffmeister of the Uni-
versity of Illinois Museum of Natural History; Dale
Birkenholz and Carol Forsyth of Illinois State Univer-
sity; Melvin Traylor and Emmett Blake of Field Mu-
seum; William Beecher of the Chicago Academy of
Sciences; and Harlan D. Walley and William Southern
of Northern Illinois University. Wallace LaBerge of:
the Illinois Natural History Survey, Section of Fau-
nistic Surveys and Insect Identification, identified in-
sects for us. We also benefited greatly in the prepara-
tion of the manuscript, photographs, and figures from:
the work of Eleanore Wilson and Elizabeth McConaha;
of the Survey’s Wildlife Research Section and Larry
Farlow and Lloyd LeMere, Survey Technical Photog;
rapher and Technical Illustrator, respectively. Glen
C. Sanderson provided a thorough editing of the first
draft of the paper, and Robert M. Zewadski edited
the manuscript for publication.

YELLOW-SHAFTED FLICKER
(Colaptes auratus)
(Fig. 1 and 2)

Yellow-shafted flicker remains the most precise
name for the flickers of Illinois (excepting red- op
reddish-shafted birds) despite the recent recommenda
tion that the common name for the flicker compley
be “common flicker” (Eisenmann 1973). Either name
is appropriate.

Spring Migration

Flickers have been recorded in all regions o)
Illinois at all seasons of the year, but there are well
defined spring and fall migrations throughout th

[oo] BREEDING a
= winter Boe

Dem of Geagrasty -Unw of

non : o = wt = a

Fig. 2—General distribution of the common flicker. The
range shown here may include large sections in which popula-
tions of the species are thin or even absent because of the nature
of the terrain and lack of suitable habitat. The outlined area
labelled with H's is roughly the zone of hybridization between
red- and yellow-shafted birds. The lines and arrows indicate the
approximate range limits for red-shafted birds.

state (Fig. 3). Flickers regularly migrate in the day-
time and at night, but whether the same populations
migrate both day and night is not known. The diur-
nal migrations are sometimes spectacular, particularly
along major rivers and the Lake Michigan shore, with
hundreds of birds passing a given point, singly and
in flocks, in a few hours (Widmann 1907; Nolan 1958;
Fawks 1967). Diurnal flights have been reported
much less often in spring than in fall, suggesting that
the routes differ in spring and fall. Except on the
Lake Michigan shore, the number of flickers seen mi-
grating is usually much lower in spring than in fall.
However, Robert Crompton and Frank Bellrose (per-
sonal communications) have recorded diurnal migra-
tions of flickers every spring on or near the Illinois
River, where at least a few migrating birds were seen
almost every day that observations were made in
March and April. Topographic land features, such
as large rivers, apparently concentrate the migrants,
for we see the diurnal migrations away from such fea-
tures but rarely and then usually at very low flight
densities of only a few birds per hour. The flights,

both on and off the rivers, are usually detected at
relatively low altitudes—50 to 300 feet above local
terrain. The flight directions are generally northward
in spring, often over or paralleling a river, the head-
ings varying in different places from northwest to
directly east. On Lake Michigan the headings may
be northward, paralleling the shore, or eastward
around the southern tip of the lake (Nolan 1958) .
Diurnal flights have been seen at all hours of the day,
but most commonly between 5:00 and 11:00 a.m. CST.

The night migration of flickers seems to differ in
more than timing from the diurnal migration. The
night flights are probably not concentrated at topo-
graphic features but move on broad fronts, as is typical
of long-distance night migrants in general. We have
heard flickers apparently migrating at night during
April and May in central Illinois, but much more
commonly in fall than in spring. We have heard
them at virtually all hours of the night, from shortly
after the onset of darkness (7:00 p.m. CST) to nearly
dawn (4:55 a.m. CST). Strangely, the timing of
calling differs in spring and in fall. In spring most
of the calling comes after midnight; in fall it is more
evenly distributed though with more before than after
midnight. It is possible that diurnal migrations are
merely extensions of the night flights, made conspic-
uous as birds aggregate along landscape features, but
no observations support this view as yet. A large kill
of flickers occurred about 10:00 p.m. on the night of
16 April 1960, when strong winds forced flickers and
many other night migrants into the waters of southern
Lake Michigan (Segal 1960) .

In some years in southern and central Illinois, and
more rarely in the north, increases occur in the flicker
population in February (Lyon 1921b; DuMont 19470),
perhaps indicating the start of the spring migration.
Much more commonly the onset of the migration
throughout the state is noted during March (Fig. 3;
Cooke 1885a and 1888; Musselman 1913), varying
year to year from early to late March (Widmann
1907) . The early part of the migration often coincides
with robin migrations (Cooke & Widmann 1884).
Peak numbers occur from mid-March to mid-April in
southern Illinois and from late March to late April
in central and northern Illinois (Fig. 3). At Chicago
Beal (1886) recorded on 17 April a great wave of
flickers, which had departed by the 23rd. Migrant
flickers are often seen at this season foraging in pas-
tures in flocks of a dozen or more birds.

Distribution

The complex of flickers, including both yellow-
shafted and red-shafted, occurs throughout much of
North America and Mexico and south to Nicaragua.
In winter the range of the yellow-shafted flicker con-
tracts mainly into the eastern and central United
States (Fig. 2).

BIRDS COUNTED PER DAY

o 500+

+
100== — 100/uR a | _® 100
MIGRATING
(LAKE MICHIGAN)
60
40

EGG LAYING
(SPAN OF DATES)

O20 SO Se e19) 29-5 Oto 28
MAR

APR MAY JUN

MAR APR MAY

40

20

a a

10 20 30
MAR

s) nS) 73

APR MAY JUN

Fig. 3.—Egg-laying and migration seasons of the yellow-shafted flicker in different regions of Illinois (see Fig. 5 for regions) . Spring)
and fall graph lines show the higher daily count of each 4 days (1967-1970). Hollow circles represent counts made in other years
or by other observers. Shaded areas show the span of dates during which egg laying has been recorded.

Yellow-shafted flickers almost certainly nest in
every county in the state, but their true distribution
is still unknown (Fig. 4).

Nesting Habitats and Populations

The 1957-1958 state censuses showed the flicker to
be the most common woodpecker in Illinois, and this

6

Bo 2a LC A0) 50

180

MIGRATING

O51

NORTH

10 20 30° 9 19 29 10 20 30 eORZ0m0

JUL AUG SEPT OCT
(e)
Js0° 0 Se
CENTRAL HR 106/HR = 81/HR
MIGRATING MISS.Q/6/ a
Ses ce O60 HR 73/uR
ie if Q 50/ur

SEPT OCT

2
MIGRATING HREb

JUL

AUG

ranking in population probably has not changed. As
a cavity-nesting species like other woodpeckers, the
flicker requires at least medium-sized trees for nest
sites. However, the flicker is less a forest species than
any other Illinois woodpecker though the red-head’
shows similar habitat preferences. Both species show)
affinities for more open habitats and edge situations.

YELLOW-SHAFTED FLICKER
BREEDING RECORDS

NESTS OR YOUNG
@ 1950 —
A 1900-1949

M BEFORE 1900

JUNE RECORDS
© 1950—
A\ 1900 — 1949

O BEFORE 1900

See ee et@MO! awd:

\ i [Eas clan
| po @rounn sonra | a Y ¢

ie )

Fig. 4.—Breeding records of the yellow-shafted flicker in IIli-
nois. Hollow symbols represent birds seen or heard in June.

In forest areas flickers tend to avoid the interior and
occupy the forest edge (Hankinson 1915; Kendeigh
1941). The most striking difference in summer hab-
itat between the flicker and the red-headed wood-
pecker is the flicker’s greater use of urban residential
habitat (Tables 1 and 10).

Grass foraging areas are important to the flicker
(Swink 1959), and pastures have been a significant
habitat for the species (Table 1).

The comparative censuses of 1907-1909 and 1957—
1958 showed that both the flicker and red-head under-
went drastic population reductions—on the order of
90 percent in about 50 years in Illinois. The change
was caused by something besides the loss of habitat,
because the densities of populations declined in nearly
all habitats (Table 1). A loss of habitat acreage
would not necessarily change population densities. As
late as the 1930’s observers in northern Illinois be-
lieved the flicker population was increasing (Fifrig
1930a and 1938; Blocher 1934). In 1933 in a four-
block area of Congress Park, Illinois, Bodensten (1934)
counted 22 flicker nests—a very high density not even
approached in recent decades. The decline after 1930
coincides strikingly with the establishment of the star-

ling population in the state. The starling was still
rare in Illinois in 1928 (Eifrig 19306), but its pop-
ulation grew rapidly in the 1930's, competing increas-
ingly with the native cavity nesters. In urban residen-
tial habitat, where flickers and starlings are perhaps
most competitive, flicker and starling populations are
inversely correlated (Graber & Graber 1963).

The reduction in densities of flicker populations
could also have resulted to some extent from a dete-
rioration of habitat quality, e.g., the loss of nest trees
from pastures, but there have been no quantitative
studies to demonstrate such changes. Besides the de-
cline in population densities, some of the overall pop-
ulation decline can be attributed to the loss of acreage
of some favorite nesting habitats, such as hedge rows,
savannahs, orchards, and pastureland.

Since the time of the first statewide censuses (1907),
flicker populations have apparently always been high-
est in the northern region of the state, lowest in the
south (Table 1). This difference is not merely a
matter of habitat availability, as population densities
have been consistently higher in the north regardless
of habitat. Why habitats in the north support more
flickers than the same habitats in the south is a ques-
tion that warrants investigation. The flicker’s pop-
ulation decline, although statewide, was particularly
severe in the south for reasons not clear. Our sub-
jective impression is that the flicker population has
been increasing in recent years, particularly in the
south.

Nest sites of flickers mentioned in the Illinois
literature are listed in Table 2. Nests are often lo-
cated in dead trees and in softwood species, such as
poplars, usually in the trunks. Burns (1900) felt that
flickers rarely excavated completely sound (healthy)
trees. Many observers noted that nest trees were large
or old (Strode 1888; Silloway 1906; Schafer 1933;
Work 1933). As the nest chamber may be 6-7 inches
in diameter (Ford 1939), at least one fair-sized tree
is required in such open nesting habitat as pasture.
The essential requirements for flicker habitat have
never been determined.

Published data on 46 flicker nests, mainly in north-
ern and central Illinois, showed the height to vary
from 4 to 45 feet (average: 16 feet), with no obvious
preferred height.

Data on flicker territory size are scant. One terri-
tory measured by Calef (1953a and 1953b) in McLean
County was 1.55 acres, a small area by comparison
with territories of the red-bellied woodpecker (Calef
1953a). A study of territory size in more open savan-
nah habitat versus forest-edge would be particularly
interesting.

Nesting Cycle

The homing of flickers to the same nesting terri-
tory—even to the same nest cavity between years—has

7

Taste 1.—Breeding populations of yellow-shafted flickers in various Illinois habitats.

Habitat

Suburban residential
Urban residential
Urban residential
Urban residential
Modified woodland
(human housing)
Unmodified woodland
Oak-maple forest
Oak-maple forest edge
Oak-maple forest edge

Oak-maple forest
Forest (all types, including edge)

Forest (all types, including edge)
Forest (all types, including edge)
Forest (all types, including edge)
Virgin floodplain forest

Mature bottomland forest

Mature bottomland forest

Grazed bottomland woods
Mature upland forest

Upland second-growth forest

Upland oak-hickory
Second-growth hardwoods

Woods (unspecified)
Woods (unspecified)
Orchard

Orchard

Late shrub

Shrub area

Shrub area
Swampy prairie

Pasture
Pasture
Pasture
Pasture

Pasture

Pasture

Birds per Type of Region or
AE 100 mee wees ee County Reference
8 50 1916 Nest Richland (S) » Cooke 1916
160 6 1958 Strip North Graber & Graber 1963
75 8 1958 Strip Central Graber & Graber 1963
98 4 1958 Strip South Graber & Graber 1963
28 29 1937 Nest Lake (N) Beecher 1942
27 22 1937 Nest Lake (N) Beecher 1942
55 0-7 1927-1943 Map Champaign (C) Kendeigh 1944
(avg 3.2)
1.25 0-8° 1944-1957 Map Champaign (C) Kendeigh 19486; Kendeigh
miles* (avg 3.1) & Gillespie 1955
1.25 8-22° 1958-1974 Map Champaign (C) Kendeigh 196056; Kendeigh
miles‘ (avg 14.0) & Brooks 19646
64 3 1943 Map Champaign (C) —_‘ Johnston 1947
177 5-6 1957-1958 Strip North Graber & Graber 1963
(avg 5.6)
214 2-3 1957-1958 Strip Central Graber & Graber 1963
(avg 2.3)
60 5-13 1907, 1909 Strip South Graber & Graber 1963
(avg 10.0)
340 0 1957-1958 Strip South Graber & Graber 1963
77 4 1948 Map Sangamon (C) Snyder et al. 1948
63 3-6 1950-1951 Map McLean (C) Calef 1953a
(avg 4.8)
1,077 0-7 1973-1975 Strip South This paper
(avg 0.7)
53 7 1955 Map Macon (C) Chaniot & Kirby 19556
479 0-2 1974-1975 Strip South This paper
(avg 0.4)
56 411 1941-1944 Map Sangamon (C) Robertson 19415, 19426,
(avg 7.3) 1944b
24 13 1967 Map Hancock (C) Franks & Martin 1967
15 27-40 1937-1938 Map Rock Island (N) _ Fawks 1937, 1938
(avg 33.3)
20 0-10 1914-1916 Nest Rock Island (N) J. J. Schafer (unpublished
(avg 3.3) notes 1914-1923)
54 0-9 1917-1923 Nest RockIsland (N) J. J. Schafer (unpublished
(avg 6.0) notes 1914~1923)
45 421 1907, 1909 Strip South Graber & Graber 1963
(avg 11.1)
78 0 1957-1958 Strip South Graber & Graber 1963
21 32 1966 Map Vermilion (C) Karr 1968
32 0-6 1957-1958 Strip North . Graber & Graber 1963
(avg 3.1)
181 0 1957-1958 Strip Central & South Graber & Graber 1963
64-67 3-9 1941-1944 Map Sangamon (C) Robertson 1941a, 1942a,
(avg 6.1) 1944a
193 17 1909 Strip North Graber & Graber 1963
279 3 1957-1958 Strip North Graber & Graber 1963
442 8-15 1907, 1909 Strip Central Graber & Graber 1963
(avg 10.4)
172 0-2 1957-1958 Strip Central Graber & Graber 1963
(avg 1.2)
882 3-4 1907, 1909 Strip South Graber & Graber 1963
(avg 3.3)
120 0 1957-1958 Strip South Graber & Graber 1963

« All figures were converted to birds per 100 acres (territorial males or nests X 2).
> S refers to the southern region of Illinois, C to the central, and N to the northern region, as shown on winter distribution maps, e.g., Fig. 5.

© These entries are miles of forest edge and birds per mile of edge.

been demonstrated from banded birds in northern
Illinois (Lyon 192la; Smith 1925; Lincoln 1927) .
The familiar “wick-er—wick-er’” call may be heard
in any month of the year in Illinois, but calling in-
creases in February and March through May. Court-

8

ship and territorial displays, often seen through

March and April (Musselman 1934-1935; Craigmile

1945), are interesting and fairly complicated in pat-
tern (Egan 1923). Particularly in April we have seen
heated territorial fights between two flickers, strug-

TasBe 2.—Nest sites of yellow-shafted flickers in Illinois.

: Number
pire of Nests

Apple tree* 15
Dead stub (unidentified tree) 13
Oaks (bur, white, blackjack, red, & unspecified) 2) || 1
Oak (dead) 4 |l
Elm (unspecified) 1 8
Elm (dead) 7
Poplar (unspecified) a | 7
Cottonwood (dead) 3 {
Willows (black and unspecified) 6
Bird houses 6
Maples (silver and unspecified) 3
Ash (unspecified) 2
Catalpa (unspecified) 1
Pine (dead) 1
Shagbark hickory 1
Walnut 1
Hackberry 1
Locust (unspecified) 1
Building 1
Telephone pole, fencepost 2

Total 81

4 Scientific names are not given, as scientific names were not provided
in the original sources.

gling on the ground often in open grass areas. In
April and May pairs of flickers are also often seen
mating. Ridgway (1923) noted that in southern IIli-
nois flickers were paired by 7 March. There is little
in the Illinois literature about “drumming” behavior
by flickers, either of a descriptive nature or on its
timing or function (Craigmile 1945).

The same nest tree and even the same cavity may
be used year after year by flickers (Silloway 1906;
Schantz 1954-1935) and sometimes by the same bird(s)
(Lyon 192la). Schantz (1934-1935) observed flickers
nesting in a dead cottonwood at Berwyn every year
from 1931 to 1933, each year excavating a new hole.
We have observed the excavation of cavities in dif-
ferent parts of the state, particularly in April and
May. Eifrig (1930b) noted that cavity excavation
took 3-4 days at one nest, but other observers give
the time requirement as a week to 20 days or more
(Burns 1900). Cavities of 11 (mainly northern) Illi-
nois nests varied from 8 to 24 inches in depth (average
15.5 inches). One tree cavity used by flickers was 6
inches in diameter. Ford (1939) recommended di-
mensions of nest boxes for flickers as (in inches) :
floor, 7 X 7; depth, 16-18; entrance above floor, 14-16;
and entrance hole, 21% inches in diameter, the box
to be placed 6-20 feet high.

No nest structure other than the cavity is made,
the eggs being laid on the wood chips and dust on
the floor of the cavity.

The eggs, typical of woodpeckers in general, are
immaculate white. Data on 49 clutches from old
(1879-1915) museum records and literature, mainly
from northern and central Illinois, had this distribu-

tion: 5 eggs, 4 sets; 6 eggs, 13; 7 eggs, 9; 8 eggs, 10;
9 eggs, 8; 10 eggs, 4; 12 eggs, 1. Average clutch size
for the 49 sets was 7.45 eggs. As the early oologists
tended to save and publish on large sets particularly,
the above distribution may be distorted. There are
no recent data on clutch size for the flicker.

The flicker is renowned as an indeterminant layer,
and in northern Illinois Abbott. (1897) induced (by
removing eggs as they were laid) a laying of 24 eggs
at one nest and Bodensten (1932) a laying of 33
eggs at another. Goelitz’s (1915) record of a 12-egg
set was possibly a natural clutch.

The only published data on the time requirements
of a nesting cycle for the flicker in Illinois are those
of Holcombe (1931) and Eifrig (1931). Holcombe
observed a nest in Zion that required 43 days from
the laying of the first egg (of nine) to the fledging
of the young. Assuming incubation began with the
last egg, the incubation and nestling periods together
would have been 35 days. At another nest Holcombe’s
data indicated an incubation period of about 12 days,
leaving about 23 days as the period of nestling life.

There are no data on nesting success for any
Illinois population of flickers, nor is it known whether
more than one brood is attempted.

Many references have appeared in the Illinois
literature on the subject of flickers and interspecific
competition for nest cavities. The general tone of
the comments has been that though flickers have been
well able to compete with house sparrows (Bartel
1931), they have lost cavities to starlings (Holcombe
1931 and 1938; Donovan 1934; Blocher 1936b; Smith
& DuMont 1945a). Despite the starling’s domination,
flickers may often raise broods after starlings have
nested (Schafer 1933; Moseley 1947). Bodensten
(1935) observed contemporaneous successful nests of
starlings and flickers in the same tree only 2 feet
apart. Flickers may also compete for or share cavities
with squirrels and screech owls (Strode 1888; Lyon
1930; Ford 1935; Work 1933; Hammond 1934-1935) ,
but the effects of these relationships on any popula-
tion are unknown. Use of the cavities by different
species is often staggered in time (Ford 1933). Reller
(1972) observed instances of the use of the same nest
tree (different cavities) by flickers and red-heads in
one case and flickers and red-bellies in another. In
both cases the nestings continued relatively harmo-
niously though the flickers were subordinate to both
other species during occasional instances of strife.

An interesting study of animal behavior was Lyon's
(1922) observations at a cavity used alternately by
squirrels, screech owls, and flickers, and finally by a
screech owl and flicker together. The owl apparently
brooded and perhaps even attempted to feed a brood
of young flickers, while the parent flickers continued
to feed their young even as the owl sat. This bizarre
relationship lasted at least 5 days until the flickers

9

fledged. The two species are not always so harmoni-
ous; a study by Brown & Bellrose (1943) showed that
flickers constituted 5 of 259 prey items of screech owls
in southern and central Illinois.

Fall Migration

In early August flickers generally appear to be in
worn, dirty plumage, but by the end of August some
seem to be in largely fresh plumage. Whether this
change reflects molt in the local population or an
influx of other populations, we do not know.

Frank Bellrose and Robert Crompton, Illinois
Natural History Survey, (personal communication)
have witnessed diurnal flights of flickers along the
Illinois River as early as 31 July in 1966 and reg-
ularly through August each year, but at generally low
flight densities—usually under 20 birds per hour. The
flights increase in number and density, particularly
after the first of September, to densities of 50 or more
per hour on some days (Fig. 3). These flights are
similar to the diurnal flights in spring, though on a
reverse heading and generally downstream—southwest
to west-southwest along the Illinois River in Mason
County and south along the Mississippi River in
Adams County. The birds fly singly and in flocks
“Indian file,’ each group using about the same route
on a narrow corridor and flying from tree-top level
to altitudes of 500 feet or more. Such diurnal flights
have been seen most often in the morning. The num-
ber of flights and the flight densities decline greatly
after mid-October in central Illinois (Fig. 3), but
flights have been seen as late as 21 November. In
northern Illinois on the Mississippi River the migra-
tion appears to fall off much earlier—at the end of
September (Fig. 3)—but the observed difference may
merely be annual variation. In southern Illinois we
have never detected the diurnal flights on the Missis-
sippi, and on the Ohio River the flight densities have
always been low by comparison with densities on
rivers in central and northern Illinois (Fig. 3). An
important but unanswered question is whether flight
densities are different from one side of a river to the
other. Thus far, our observations on the Ohio River
have been restricted to the Illinois side. Diurnal mi-
grations of flickers have not been reported on the
Rock and Wabash rivers but should be looked for on
these and other major streams.

At least one large diurnal fall flight of flickers has
been recorded on the Chicago lake front (Boulton &
Pitelka 1938). The diurnal migrations are not re-
stricted to’ waterways but have rarely been reported
elsewhere. Benjamin Gault (unpublished notes 1912)
counted 51 migrating flickers in 5 minutes on 19
September at Glen Ellyn, and we have seen light mi-
grations (three birds per hour) in November in Pope
County away from the Ohio River.

In the same period that diurnal migrations of
flickers are most evident, there are regular nocturnal

10

@ 1950-

migrations of the species. We have heard flickers ap-
parently migrating over central Illinois on many
nights between late August and the first week in
October. These flights were not obviously associated
with waterways or other landscape features, but were
audible at various stations across the state at all hours
of the night.

Flickers are relatively uncommon victims in the
kills at television towers in central Illinois. We have
records of only eight flickers among approximately
12,000 birds of all species picked up and identified
from the towers. The flickers were killed between
27 September and 7 October, a relatively small part
of the fall migration period when the migrant flicker
population is at its maximum (Fig. 3). These data
differ somewhat from those in Graber (1968), reflect-
ing a great increase in the amount of field data since
that paper was submitted. The low kill of flickers is
puzzling in view of the number of flickers seen in
the fall. The data seem to imply that most of the
migration is diurnal. Are different populations in-

YELLOW-SHAFTED FLICKER
WINTER RECORDS
DEC. 15 -FEB.1

1900 — 1949

M BEFORE 1900

Livin

~ KOGAN
maghano C

Fig. 5.-Winter records of the yellow-shafted flicker in IlIli-
nois. Heavy horizontal lines separate the three regions (north,
central, and south) referred to in the text.

volved in diurnal versus nocturnal migration in this
species?

Lyon’s (1925) record of a flicker banded at Wau-
kegan in June 1918 and recovered at Monroe, Lou-
isiana, in July 1925 seems to place an Illinois breeding
bird deep in the winter range at a very early date.
Probably more representative of the actual migration
movement for the species is a flicker banded at Zion
in June 1930 and recovered at Hamilton, Alabama,
9 October 1930 (Cooke 1937). Seven published rec-
ords of flickers banded mainly in summer in northern
Illinois and recovered mainly in winter are remark-
ably consistent in location at two areas—northeastern
Louisiana and northwestern Alabama (Lyon 1925;
Anonymous 1931; Cooke 1937 and 1946; Lincoln 1939;
Labahn 1941) .

Our counts for southern Illinois (Fig. 3) show
an abrupt increase in the flicker population after
20 September, probably representing large influxes of
more northern populations, which stand out because
of the relatively low breeding population in the south.

The ratio of our spring-to-fall counts of foraging
flickers, i.e, excluding birds in actual migration
flights, does not indicate high productivtiy. In north-
ern Illinois, we saw 1.0 flicker in spring (March—
May, inclusive) to 1.1 in fall (August-October, in-
clusive) , whereas the ratio in the central region was
1.0 to 1.5 and in the south 1.0 to 2.2. East-central
Illinois had higher fall populations than had west-
central Illinois (1.6 to 1.0) though the spring pop-
ulations were nearly the same.

Winter Populations

Yellow-shafted flickers may be found in virtually
all parts of the state in winter (Fig. 5), and the num-
ber of flickers statewide may be nearly as great as
the summer population. However, in winter most
(70-80 percent) of the state’s flicker population is
concentrated in southern Illinois. Most of the rest
of it is in central Illinois with relatively little of it
in the northern region (Graber & Graber 1963).

This distribution is also indicated in the Christ-
mas counts (Fig. 6); the average number of flickers
per party hour (1945-1975) is nearly six times as
great in the south as in the north and two times as
great in the south as in the central part of the state.
Occasionally large flocks of flickers may be found
even in the north in winter (Blake 1948).

Early in this century, when corn was hand picked
and large areas were left with stalks standing, corn-
fields were a favorite winter habitat for flickers (Ta-
ble 3). Corn stubble left from mechanically picked
corn does not support nearly such high population
densities of flickers. However, it is still an impor-
tant foraging habitat because there is so much of it,
and it is still used even though at low densities. For-
est, shrub areas, and pastures are also regularly used

BIRDS PER PARTY HOUR

1905 15 25 35 45 55 65 1975

Fig. 6.—Yellow-shafted flickers seen per party hour on Au-
dubon Christmas counts in the three regions of Illinois. Each
point represents a 5-year average.

winter habitats. In the south we have found bottom-
land forest to have consistently higher populations
of flickers than upland forest (Table 3). Urban
habitat appears less important to the flicker in win-
ter than in summer. The reference in Graber &
Graber (1963: 474) to hayfields as winter habitat for
flickers, including the population density cited (6
birds per 100 acres) is erroneous. Hayfields are not
important as winter habitat, and we are totally at a
loss to explain the error.

Winter flicker populations in five upland and
eight bottomland woods in southern Illinois were ex-
amined to see if any correlation existed between the
bird and the woody vegetation in these woods (see
introduction). Flicker populations were also com-
pared with those of other woodpeckers in the same
woodlands. The only correlation found (r= 0.597,
P=<0.1) indicated that flicker populations are
highest in bottomland woodlands that have over 20
percent of the basal area of their trees in the small
tree category. Winter numbers were 5-13 times as
great as those in summer in these bottomland woods
and 7-8 times as great as those in summer in the up-
land woods.

Though at least part of the Illinois breeding pop-
ulation of flickers winters well south of Illinois (see
under Fall Migration), the sources of the Illinois
winter population are not known.

Food Habits

The flicker is well known as a consumer of ants
(Forbes 1882a; Ekblaw 1919). Gross & Forbes (1909)
stated that ants made up 45 percent of the flicker’s
diet. Much of the food is taken from the ground. A
specimen taken in Tazewell County 24 May 1881

1]

TABLE 3.—Winter populations of yellow-shafted flickers in various Illinois habitats.

é Birds per Years Type of Region or
Habitat a 100 Acres (January) Census County SCRE:
Urban residential 191 0.5 1976 Strip Central This paper
Urban residential 191 1 1976 Strip South This paper
Suburban woodlot 20 0-5 1968-1972 Map Lake (N) * Miller & Miller 1968, 1970
Oak-maple forest edge 55 0-16 1925-1943 Map Champaign (C) Kendeigh 1948a
(avg 7.3)
Oak-maple forest edge 1.25 o-1» 1944-1948 Map Champaign (C) Kendeigh 1948a
miles” (avg 0.2)
Oak-maple forest edge 1.25 0-3" 1949-1975 Map Champaign (C) Kendeigh & Brooks 1963a;
miles (avg 1.4) Kendeigh, James, & Weise
1953
Forest (all types, including edge) 110 0 ae Strip North Graber & Graber 1963
1957-1958
Forest (all types, including edge) 152 0-1 1957-1958 Strip Central Graber & Graber 1963
(avg 0.5)
Forest (all types, including edge) 241 2 1907 Strip South Graber & Graber 1963
Forest (all types, including edge) 211 2-7 1957-1958 Strip South Graber & Graber 1963
(avg 3.8)
Mature upland oak-hickory forest 772 0-11 1974-1976 Strip South This paper
(avg 2.5)
Mature bottomland forest 1,398 0-24 1974-1976 Strip South This paper
(avg 5.3) ¢
Bottomland woods 50 (+) *-2 1950, 1953 Map Cook (N) Montague 1950, 1953
Virgin bottomland forest 50 a 1947 Map Piatt (C) Fawver 19476
Grazed bottomland woods 53 2 1955-1957 Map Macon (C) Chaniot & Kirby 1955a,
1956; Kirby & Chaniot
1957
Shrub area 87 0 1957-1958 Strip North & Central | Graber & Graber 1963
Shrub area 101 2-5 1957-1958 Strip South Graber & Graber 1963
(avg 3.0)
Shrubby field and forest edge 85 (+) -1 1955-1956 Map Richland (S) Shaw & Stine 1955; Shaw
et al. 1956
Shrubby field 40 (+) -2 1960-1965, Map Lawrence Shaw 1961, 1962
1968
Pasture 440 (+) 1907 Strip North Graber & Graber 1963
Pasture 343 1 1907 Strip Central Graber & Graber 1963
Pasture 208 3 1907 Strip South Graber & Graber 1963
Pasture 93 1-4 1957-1958 Strip South Graber & Graber 1963
(avg 2.1)
Cornfields (harvested) 491 (+) 1957 Strip Central Graber & Graber 1963
Cornfields (stalks standing) 222 8 1907 Strip South Graber & Graber 1963
Cornfields (stalks removed) 117 2 1907 Strip South Graber & Graber 1963
Cornfields (machine picked) 277 1-2 1957-1958 Strip South Graber & Graber 1963
(avg 1.4)

aN refers to the northern region of Illinois, C to the central region, and S to the southern, as shown on winter distribution maps, e.g., Fig.5.

> These entries are miles of forest edge and birds per mile of edge.
© The plus symbol (+) indicates fewer than one bird per 100 acres.

had eaten nothing but ants. Similarly, a male from
Champaign County on 3 October 1968 had packed
in its stomach and esophagus 20 milliliters of ants
(mainly adults with some pupae), 90 percent of
which were one species of Formica, plus species of
Lasius and Acanthomyops. (A species of Lasius was
also used in anting by a flicker (Southern 1963) ).
This bird’s food and its fresh undigested condition
indicated that the bird had fed in several different
areas in a brief span of time and in different habitats
from open fields to woods (Wallace E. LaBerge, IIli-
nois Natural History Survey, personal communica-
tion). Forbes (1881) found no indication of preda-
tion on canker worms by a flicker taken in a heavily
infested orchard. In the deep south, at least, the
flicker is a very important predator on corn borers

12

(Black et al. 1970), and though this has apparently
not yet been reported in Illinois, the large winter
population of flickers in corn stubble in Illinois may
relate to such predation. In Georgia flickers have
also been observed feeding on corn ear caterpillars
of an undesignated species (Dorsey 1925), and flickers
are an important predator on the southwestern corn
borer in Arkansas (Wall & Whitcomb 1964).

Beal’s (1911) extensive study of the food of North
American woodpeckers includes some data on Illinois
specimens. Beal found that the yellow-shafted flick-
er’s diet was about 61 percent animal matter and 39
percent vegetable. Ants were clearly the favorite food
every month, comprising about 50 percent of the
year’s diet and going as high as 80 percent in May
and as low as 11 percent in December. Predaceous

ground beetles (Carabidae), Hemiptera (chinch
bugs), and Orthoptera (grasshoppers, crickets) were
regular items in the diet in small amounts.

Small, mainly wild, fruit was important in the
flicker’s diet from summer to October, when such
fruit constituted about 42 percent of the food. Espe-
cially important were species of Rubus (blackberries,
raspberries, etc.) and Rhus (poison ivy, sumac), plus
wild black cherries, hackberries, grapes, and dog-
wood. The flicker may be an important agent in the
distribution of such plants. In the fall we have often
seen flickers feeding on the fruit of poison ivy. They
also eat pokeberries and wild grapes (Comfort 1940) ,
and Gault (1932) found one eating pears on a tree.
Flickers are also fond of suet (Patterson 1923).
There is no definite reference to the use of mast by
flickers in Illinois in contrast to the abundant liter-
ature on the subject for red-headed woodpeckers.

Longevity and Mortality

Survival and longevity of flickers have not been
studied systematically on a population basis in IIli-
nois. The two oldest flickers for which band recover-
ies have been published were at least 7 years and 1
month (Lyon 1925) and 5 years (Remington 1944) .
The remains of at least a few flickers have been
found in Indian kitchen middens dating back per-
haps 10,000 years (Baker 1936; Parmalee 1959, 1962,
and 1969). More recent problems with humans re-
late to possible insecticide poisoning (Scott et al.
1959) and highway mortality (Flint 1926 and 1934—
1935; Komarek & Wright 1929; Blocher 1936a; Star-
rett 1938). Some flicker mortality has been ascribed
to severe weather in winter and spring (Schafer 1921;
Roseberry 1962) . ‘

The screech owl and red fox have been recorded
as predators, or at least scavengers, on flickers in
southern and central Illinois (Brown & Bellrose 1943;
Knable 1970). Coffin (1970) described a strange in-
terplay, apparently unrelated to predation, between

a flicker and a sparrow hawk. Perhaps unique was

if

the instance of a flicker made unable to fly because
of heavy poplar resin accumulations on its wings and
tail (Brodkorb 1928) .

The only reference we’ve found on the pathology
of flickers in Illinois is Labisky & Mann (1961) ona

case of avian pox.

RED-SHAFTED FLICKER
(Colaptes auratus subspecies)

There are a number of Illinois records of flickers
with reddish color in their flight feathers (Ridgway
1914; Lyon 1934; Labahn 1941; Comfort 1949; Mum-
ford 1959a and 1959b; Southern 1962; Petersen 1966

/ and 1967; Anderson 1966 and 1971; Fawks 1967; Test

1969; Hamilton 1969; Kleen & Bush 1971). The
genetic constitution of Illinois red-shafted flickers is

unknown, but presumably includes mainly hybrids
between auratus and cafer. In those cases where red-
shafted specimens have been examined ‘in hand,’
they have invariably proved to be hybrids (Ridg-
way 1881 and 1914; Lyon 1934 and 1934-1935; La-
bahn 1941; Coursen 1941; Southern 1962; Test 1969) .
There is no certain way to differentiate specimens
(even in hand) of pure cafer from hybrids close to
the (cafer) parental stock, and virtually every conceiy-
able stage of intermediacy between cafer and auratus

RED- SHAFTED FLICKER
AND FLICKER HYBRIDS

@ 1950-
A 1900-1949

@ BEFORE 1900

Fig. 7.—Distribution of records of red-shafted and hybrid
flickers in Illinois. Heavy horizontal lines separate the three
regions of the state.

has been recorded in the hybrid zone (Fig. 2). Hy-
brids close to awratus are probably regularly misiden-
tified in the field as awratus. The only attempt to
determine frequency of hybrid types among Illinois
flickers was that of Ridgway (1881), who examined
30 specimens collected in the fall near Mt. Carmel
and found only one that showed any sign of hybrid-
ization. However, he.thought | in 200 a more likely
incidence of the hybrid phenotype.

Red-shafted birds are most often reported in the
fall, but a few may overwinter in Illinois (Fawks

13

Paik

=

es

Pileated woodpecker

Photo taken in June,
north of Golconda,. Illi-

Fig. 8.
at its nest.

miles

5

4
bel
(3)

a4
[s}
A.

LSy3
Be
me

3
Ow
poo

ac} 5)

N
‘a o
HS
o
ois}

a} ©)
(oye)
Ss

14

1967; Petersen 1967) , especially in the west and south-
western parts of the state.

The dates of reports of “‘red-shafted” flickers ex-
tend from 30 August to 22 May, and the distribution
of these records is shown in Fig. 7. The influx of
these reddish-shafted birds would seem to indicate
that at least some of our winter flickers are from the
north or northwest.

There are two obviously erroneous reports of red-
shafted flickers in the literature in the Christmas
counts, namely the Danville count for 1954 (Anon-
ymous 1955) and the Princeton count for 1958
(Kramer 1959). In both cases 10 red-shafted but no
yellow-shafted flickers are listed.

PILEATED WOODPECKER

(Dryocopus pileatus)
(Cover and Fig. 8 and 9)

Distribution

The pileated woodpecker is widely distributed
in the forested regions of North America (Fig. 9).
The distribution of the pileated, despite its con-
spicuousness is poorly known in Illinois (Fig. 10).

2100 400000 _go
mien
Dept of Geography - Univ. of \ihinors hoe vot so Pee __ jr}

Fig. 9.—General distribution of the pileated woodpecker. The
range shown here may include large sections in which popula-
tions of the species are thin or even absent because of the
nature of the terrain and lack of suitable habitat.

PILEATED WOODPECKER
BREEDING AND OTHER RECORDS

NESTS OR YOUNG

@ 1950 —

A 1900-1949

M@ BEFORE 1900
SUMMER RECORDS
JUNE-JULY
O 1950 —
= apsif ok
A 1900 — 1949 parca, [oonowen fee cela
Se cen ee
O BEFORE 1900 |W Se AW aoe
OTHER RECORDS @ yiMATT tee we
S MARCH-MAY TC weomcan, | sercanor jpouctas :
F AUGUST-NoveMBER \’'"* \i \ ST ote | el
W DECEMBER-FEBRUARY Wo“ | | | Sera
2 UNDATED Soh wacousic! wontcomeny |) Fuwpemano) °°"

;
steal) oa IC oa =e
—— —1 — SF aye ee casera

inh i coca)

wroson ) 00 |

Fig. 10.—Breeding and other records of the pileated wood-
pecker in Illinois. Since the bird is non-migratory, winter,
spring, and fall records have been added to show the pattern of
distribution more clearly.

There is no evidence of migration by any Illinois
population of the pileated woodpecker. Fluctuations
in the spring and fall counts of pileateds (Fig. 11)
were probably related to seasonal changes in behavior
which affected the conspicuousness of the bird rather
than to changes in numbers. Our counts definitely
increased at times when the species became noisy,
either calling or drumming. In New York, Hoyt
(1941) found that pileateds remained in the same
area throughout the year. Though we have plotted
winter records separately (Fig. 12), in view of the
species’ sedentary nature the winter records may also
be indicative of breeding populations. Consequently,
we have included some winter, as well as spring and
fall, records in Fig. 10 to provide a more complete
picture of the pileated’s distribution.

Within historic times the pileated has undergone
at least one major cycle of distribution regression and
re-expansion in Illinois. The picture is somewhat
complicated in that perhaps two distinct populations
were involved, the northern (D. pileatus abieticola)

15

10

BIRDS COUNTED PER DAY

12 24
APR

12 24
MAY

12 24
FEB

12 24
MAR

ia LAYING (ONE RECORD ONLY)

OO

12 24

12 24

CENTRAL

12 24
AUG

12 24

JUN JUL

SOUTH

O

EGG LAYING

eye)
ome)

12 24
JUL

oO

12 24
OCT

12 24
AUG

12 24

JUN SEE

Fig. 11.-Numbers of pileated woodpeckers seen in spring, summer, and fall in central and southern Illinois. The graph line
represents the higher daily count of each 4 days made by R. R. Graber in 1967 and 1970 in southern Illinois and in 1969 in central
Illinois. Hollow circles represent counts made in other years or by other observers. The egg-laying period (shaded area) shown is

very short because of the paucity of records.

and the southern (D. p. pileatus) forms of the species.
The distribution of the two has never been known
except at the northern and southern ends of the state.
Kennicott (1853-1854), referring presumably to the
northern race, stated that it was formerly not uncom-
mon in Cook County, and forest was sufficiently ex-
tensive in the first half of the 19th century to support
populations in the northern tier of counties, in Ogle
and Kane counties and down the Mississippi valley
(Anderson 1970). In northeastern Illinois Nelson
(1876-1877) found the pileated to be a rare winter
visitant. There is no indication that the northern
race has been common in Illinois since then except
near the Mississippi, where the species may have sus-
tained itself through the years (Johnson 1936 and
1941).

In the south Ridgway (1881la) found the southern
pileated to be sixth in abundance of the common
species of woodpeckers, though in some localities
fourth or fifth, which is very similar to its present
ranking. Ridgway (1915) later noted that the pile-

16

ated population had become much reduced. Vander-
cook (1919) observed a similar reduction on the
Kaskaskia River. In central Illinois Strode (1911)
noted the disappearance of the pileated on the Spoon
River about 1900. The noted oologist R. M. Barnes
(1890 and 1912) did not find the species in Marshall
County, nor did Loucks (1891) in the Peoria area.
The timing of these observations suggests that all of
the authors were witnessing the same change. The
cause of the change can only be surmised, but it was
probably related to the pileated’s requirement of ex-
tensive forest habitat and the widespread deforesta-
tion of Illinois in the 19th century (Graber & Graber
1963). The declining trend in forest acreage was re-
versed between 1910 and 1920 (King & Winters
1952), after which pileated habitat probably im-
proved both in quality and quantity. The wood-
pecker responded, and Jones (1934) made an early
reference to its recovery in the St. Louis area, where
much earlier Hurter (1884) had found the pileated
rare. Musselman (1926) suggested that the pileated

PILEATED WOODPECKER
WINTER RECORDS

DEC.— FEB.
Wy

40 DaMESS | STEPHEN:

@ 1950- ae feet an be
2 como |g gic at
A 1900-1949 pane EY 6 —_
Js a rake ealia\
MH BEFORE 1900 (CE Se

i—-— +4 euhy )
‘ac AWRENCE
° nt na | f eo) INCE f

/

s
/ xe @.scncton | pee | | F(
( Tay ™ 42 )
\ EE

Ne) iia. eee! |
sae rom é

Pe
Jes

rey eal

: alt
OS higarge >
a ic

Fig. 12—Winter records of the pileated woodpecker in IIli-
nois. Heavy horizontal lines separate the three regions of the
state.

may never have disappeared from the heavily wooded
islands of the Mississippi near Quincy. In the 1950's
and 1960’s the expanding population of pileated
woodpeckers was noted by many observers (Mayfield
1951; Nolan 1955; Petersen 1964) as far north as
Rock Island, Whiteside, and Marshall counties (Shaw
1959; Brown 1964; Fawks 1967).

Except for northwestern Illinois, the population

D. p. pileatus moving northward along major streams.
With the exception of northeastern Illinois, the range
of this species is probably now near its maximum
19th century limits, reaching north into Vermilion
and Piatt counties in the east, at least to Putnam
County on the Illinois River, and the full length of
the state on the Mississippi (Fig. 10 and 12). The
recent Ogle County records are particularly interest-
ing in view of the complete absence of records for
Winnebago County. This suggests expansion from
the south along the Rock River, which is thinly for-
ested in many places.

There is no evidence that pileateds ever occupied
at any significant or sustained population level the
prairie peninsula of eastern Illinois from Kane
County south to Iroquois, Champaign, and McLean
counties.

Nesting Habitats and Populations

There is a strange dearth of references to the pi-
leated woodpecker’s habitat in Illinois. Only Ridg-
way (1889), in referring to the habitat as “the more
heavily timbered portions,” and Musselman’s (1926)
reference to “heavy woods on the Mississippi River
islands” indicate the habitat.

Judging from population densities in southern
Illinois (Table 4), we conclude that bottomland for-
est is definitely favored over upland by pileateds.
An old bottomland forest, Beall Woods (Wabash
County), had the highest population (6.9 pileateds
per 100 acres) of any area censused.

Our studies on bird populations in relation to
forest vegetation in southern Illinois showed that pi-
leated woodpecker populations were poorest in those
bottomland forests with a high Importance (Y) of
oak-hickory. The correlation (r) between pileated
populations and oak-hickory in eight forest study
areas was —0.780 (P= 0.02). No pileateds were de-
tected in two bottomland forest areas which had oak-
hickory Importance values of 64.2 and 97.8. Impor-
tance of oak-hickory in woodlands with pileateds was
26.5, 32.7, 50.0, 34.8, 28.9, and 31.0 (listed in descend-
ing order of pileated populations). Pileated popula-
tions were higher in woods having a more even bal-

expansion appears to have come from the south, i.e., ance between oaks, hickories, maples, elms, Celizs,
Taste 4.—Breeding populations of pileated woodpeckers in various Illinois habitats.
x Birds per : Type of Region or
Habitat Acres 100 Acres Years Geneus County Reference

Forest (all types, including edge) 340 1-2 1957-1958 Strip South Graber & Graber 1963
(avg 1.5)

Virgin bottomland forest 77 3 1948 Map Sangamon (C) * Snyder et al. 1948

Mature bottomland forest 913 0-7 1974-1975 Strip South This paper
(avg 1.2) ’

Mature upland forest 479 0-0.5 1974-1975 Strip South This paper
(avg 0.2)

4 C refers to the central region of Illinois, as shown on winter distribution maps, e.g., Fig. 5.

17

ashes, and sweet gums. There was a positive correla-
tion between the number of pileated woodpeckers
and the number of large (over 22 inches DBH)
Celtis (r= 0.894, P < 0.01) in bottomland tracts.

It is not surprising that pileated populations were
much lower in upland forest (Table 4), where oak
and hickory are the characteristic dominants. The
only upland woods (of five censused) having a mea-
surable pileated population within the census tran-
sect was adjacent to a bottomland with a high pop-
ulation of pileateds. This upland woodland also had
a more balanced tree composition than most uplands,
with the Importance of oak-hickory being only 39.8.
For the upland study areas lacking pileateds, oak-
hickory Importance ranged from 54.5 to 87.0. Wnere
pileateds are found in hill land, they frequent the
valleys and ravines, where oak-hickory usually consti-
tutes less than 40 percent of the tree flora (Voigt &
Mohlenbrock 1964) .

How large a forest tract is required to sustain a
pileated population is unknown. No measurements
of pileated populations exist for northern Illinois.
Territory size has not been measured in any Ilinois
population of pileateds.

We have nest-site data for only 12 pileated nests
in Illinois. All were located in live sycamores or dead
trees and trunks. Heights of nests ranged from about
10 to 90 feet (Strode 1911), being higher in northern
and central Illinois (average for three nests: about
60 feet if the 90-foot figure is true) , than in the south
(average for six nests: about 25 feet) .

Nesting Cycle

Nothing has been recorded on the nesting cycle
of the pileated woodpecker in Illinois. For data on
populations elsewhere see Hoyt (1941 and 1944),
Hoyt (1957), and Kilham (1959).

In southern Illinois pileateds become particularly
noisy in March, loudly calling and giving their dis-
tinctive “drum roll.’’ This behavior may mark the
onset of nesting activity. Kilham (1959) has observed
mating in Maryland in late March. Off and on
through most of the year the commonest calls heard
suggest alarm—loud “kuk-kuk” notes, sometimes ris-
ing and slurred into a high cackling sound. Also
through the year, but more frequently in the spring,

TABLE 5.—Winter populations of pileated woodpeckers

we hear the loud, high, rolling “song” suggestive of
the flicker’s “song” but much more clarion.

On the basis of fledging dates and incubation (18
days) and nesting (26 days) periods given by Hoyt
(1944) and Hoyt (1957), we conclude that egg laying
occurred about 20 April at one nest in central Illinois
and 1-6 May at two nests in southern Illinois. We
would expect laying to begin much earlier in south
than in central Illinois.

While photographing pileateds at a nest in Pope
County, we observed a pair trade places in brooding
the young. ‘The male was in the cavity when the fe-
male alighted quietly on the back side of the nest tree.
Within a few seconds the male left silently. As there
had been no vocalization or tapping and as the male
could not have seen the female, he must have heard
her land on the trunk. The female waited for about
1 minute after the male departed, then came around
to the nest entrance and went in. Both adults also
fed the young, bringing food so enclosed in their bills
that we could not identify it. When the adults landed
on the nest tree, we could hear the young utter a
buzzy whirring sound audible at least 25 feet from
the nest.

There are no Illinois data on nesting success or
productivity.

Fall and Winter Populations

The dispersal of pileated woodpeckers in fall or
winter has not been substantiated with banded birds,
but there is other evidence of some movement—no-
tably the occasional appearance of pileateds in urban
areas in winter and a slight increase in the pileated
population in upland forest and a decrease in bottom-
land forest, compared with summer levels (Tables
4 and 5).

The ratio of our spring (March—May, inclusive)
to fall (August—October) counts of pileateds in south-
ern Illinois was 1.0 (spring) to 1.2 (fall), suggesting
modest productivity in summer. There is a definite
resurgence of drumming by pileateds in September
and October, making them conspicuous and prob-
ably affecting the counts, but as there is also much
drumming in spring, the effect may be evened out.
Surprisingly, our data show little difference between
summer and winter in the total population of

in various Illinois habitats.

: Birds per Years Type of Region or
SEINE ates 100 ee (January) Orie cane ES SEE
Forest (all types, including edge) 241 1 1907 Strip South Graber & Graber 1963
Forest (all types, including edge) 211 0 1957-1958 Strip South Graber & Graber 1963
Mature bottomland forest 1,398 0-7 1974-1976 Strip South This paper
(avg 0.9)
Mature upland forest 712, 0-2 1974-1976 Strip South This paper
(avg 0.3)

18

pileateds when we apply density figures to the appro-
priate habitat acreages (Graber & Graber 1976). Sum-
mer populations were slightly higher, perhaps indi-
cating that most of the production of young has
occurred by June.

Cooke (18855) saw 5-15 pileateds per day in
winter in Union County—a high population area,
where we have seen lower numbers (peak: 7 per day)
in recent years.

Winter pileated woodpecker populations are high-
est in bottomland forests with large trees (Fig. 13).
In seven of eight bottomland tracts that we studied
in southern Illinois a positive correlation existed
between the number of large trees (over 22 inches
DBH) and the number of pileateds encountered per
hour of censusing (r= 0.960, P < 0.001). A positive
correlation also appeared between pileated numbers
and the Importance (see Introduction) of Celtis (r=
0.779, P< 0.05) and Ulmus (r=0.702, P=0.05).
As in summer, there was a negative correlation be-
tween numbers of pileateds and the Importance of
oak-hickory. Habitat preference apparently does not

115

100

75
Lu
ao
O
rm 50
Be
Lu
a
rm 30:
Lu
s2
=
= 1.0° BIRD/HR.
rs
20 |
ee a es te a | ee | |e ee |
=
=

15

TU | so UO tN Se | eS

m= SMALL TREES |
5 A= MEDIUM SIZE TREES 0-0.3 BIRD/HR.

@ = LARGE TREES

F

A C B G E H

Fig. 13.—Correlation between winter numbers of pileated
woodpeckers and sizes of trees. Each vertical line represents a
separate bottomland forest. The square, triangle, and dot on
each line show size classes of trees with the square representing
trees 4-10 inches DBH; the triangle, trees 10-22 inches DBH;
and the dot, trees over 22 inches DBH. The horizontal dash
lines divide population levels of pileated woodpeckers. Letter
designations refer to specific forest tracts identified in the
introduction.

15.0
2 10.0
S ; SOUTH
=
<e 50)
a CENTRAL
S
=
may Sa
jo
wm
=
far 1.0 ZN

0.5

1940

1950

Fig. 14—Pileated woodpeckers seen per party hour on Au-

1960 1970

dubon Christmas counts in the three regions of Illinois. Each

point represents a 5-year average.

change greatly between summer and winter in this spe-
cies in contrast to those of most other woodpeckers.

‘The Christmas counts for the pileated woodpecker
show the highest annual variation of those for any
of the common woodpeckers. Annual variation in
the counts for the past 10 years ranged from 0 to 279
percent (mean =74 percent) in northern Illinois,
14-160 percent (mean= 70) in central Illinois, and
11-648 percent (mean = 114) in the south. Our own
winter censuses show only about 25 percent annual
variation. The Christmas counts show a population
gradient, declining from south to north (Fig. 14).
The species was first detected on a count made much
later in central Illinois (1955) than those on which
it was first found in the north and south (1940 and
1928, respectively), possibly reflecting the expansion
of two populations, one from the north and another
from the south with the central region being the
last reached from either end.

We have but one observation on roosting by a
pileated woodpecker. At 4:25 p.m. CST on 22 No-
vember in Pope County, a pileated entered a roosting
cavity about 25 feet high in a dead stub, which had
also been used during the summer as a nesting site
(in a different cavity 11 feet high).

Food Habits

The only Illinois reference we have found to the
food of the pileated woodpecker is that of Cooke

19

(1885b) , who found that winter specimens from Union
County were filled with ants. The stomach of a March
(1977) specimen from Vermilion County was packed
with carpenter ants (Camponotus herculeanus). Beal's
(1911) study of 80 North American specimens also
showed ants to be important in the diet. He found
the pileated’s food to be about 73 percent animal and
27 percent vegetable matter. The animal food was
about 40 percent ants and 22 percent beetles—espe-
cially the larval stages of wood borers of the families
Cerambycidae, Buprestidae, and Elateridae, probably
taken mainly from dead or decaying wood. The ants
also were of the larger species found on and in de-
caying wood. In one stomach Beal counted 2,600
ants. Other animal food included flies, caterpillars,
grasshoppers, and termites. Musselman (unpublished
notes 1968) observed pileated woodpeckers feeding
on suet. He also witnessed a red-headed woodpecker
chasing a pileated from the suet feeder.

The vegetable food was virtually all wild fruit,
such as hackberry, smilax (Smilax), blackberry, sumac
and poison ivy, holly (Ilex), grape, dogwood, tupelo,
persimmon, sassafras, elderberry (Sambucus), and haw
(Viburnum), all common plants in Illinois.

In their search for borers, pileateds often make
distinctive large holes (Fig. 15) in infested trees. We
have noted these characteristic holes most often on
sassafras, box elder, ash, cottonwood, Kentucky coffee
tree, and beech.

Beal (1911) concludes his remarks on the pileated
with an appeal for the species’ protection. Unfor-
tunately, pileated woodpeckers are often shot, because
of their large size, by ignorant hunters. Musselman
(1933) refers to four being shot in 1 week near
Quincy. Pileated remains have been detected among
Indian middens dating back perhaps 10,000 years
(Parmalee 1959; Noyes & Hill 1974).

Specimen Data

Because of the paucity of preserved specimens,
it is still uncertain whether there are (or were) two
distinct populations of pileated woodpeckers in IIli-
nois. We have examined 20 Illinois specimens, of
which 18 were in adult (i.e., not obviously immature),
not obviously worn, plumage (Table 6). Three of
the male specimens—all collected before 1900—fall
within the size range of the northern form, Dryocopus
pileatus abieticola, as given by Ridgway (1914). The
distribution of these specimens indicated a range for
that race of extreme northern Illinois, south along
the Mississippi valley to at least Hancock County.
These large males also (as in abieticola) have a
slightly grayer tone of body plumage than have spec-
imens from southern Illinois. All other Illinois
specimens—central and southern Illinois, male and fe-
male—fall within the size range of D. p. pileatus (Ta-
ble 6 and Ridgway 1914). These central and southern

20

lo ar? f . ww : eo :
Fig. 15.—Typical pileated woodpecker work on a red oak on
the Ohio River bank at Golconda, Pope County, Illinois.

-

;
-
;

|
| Tas_e 6.—Measurements of Illinois specimens (plus one from adjacent Indiana) of pileated woodpeckers, excluding

obviously worn, molting, and juvenile specimens.

| Num-
ber Culmen (from Naris)
/ Region of Illinois Months ae Gas Wing (Chord) inmm Tail Length in mm inmm
| Speci- Range Mean sD Range Mean sD Range Mean sD
mens
North and Missis- Noy.—Mar. 4 M 229-245 237.1 6.51 153-163 159.3 4.86 43-53.5 48.2 4.15
| sippi valley
| of Central
South and Central Sept.May 7 M 217-234 224.7 6.24 148-157 153.1 4.25 42-47 44.9 2.41
(except Mississippi
| valley)
South and Central Oct.-May 8 F 213-226 218.3 4.17 140-152 147.2 3.58 36-43 40.7 2.07

| (except Mississippi
valley)

;

| Ilinois specimens have almost the same size range as

have Kentucky specimens (Mengel 1965) if we use
| mean wing length + 3sp to indicate the maximum
| range for the population. Within this maximum
_ range, however, would be all of the Illinois specimens

_ but one, including even the northern specimens. We

}
:

t

'
:

have seen no recent (since 1900) specimen showing
the characters of abieticola.

We have found weight data on only four adult
specimens—three females: an April specimen from
Cumberland County, 262.2 grams; a May specimen
from Sangamon County, 237.4 grams; and one March
specimen from Pope County, 223.5 grams. The fourth,
a male, was a March specimen from Vermilion County
that weighed 278.6 grams. An immature female from
Jackson County, probably near the end of the post-
juvenile molt, weighed 209.5 grams.

RED-BELLIED WOODPECKER

(Centurus carolinus)
(Fig. 16 and 17)

Spring Populations

Do red-bellied woodpeckers migrate in Illinois?
A few authors have suggested that they do (Nelson
1876-1877; Cooke 1888; Smith & Parmalee 1955).
Hess (1910) admitted that he was uncertain about
the matter, and there are no published records to
indicate that the migration has been observed di-
rectly. We have seen what we assumed to be diurnal
migration of a few red-bellied woodpeckers on the
“blue jay routes’ of the Mississippi and Ohio valleys,
but only in fall (Fig. 18). There is no positive ev-
idence of nocturnal migration by the species (see Fall
Migration). Red-bellied woodpeckers do not vacate
any sizeable part of Illinois in winter, and the spring
populations do not show a pronounced migration
peak like those of the strongly migratory flicker and
red-headed woodpecker (Fig. 3 and 26).

The highest spring counts of red-bellies have been
recorded in February and March (Fig. 18), months

for which we have only fragmentary data. If a mi-
gration occurs in that period, it is conspicuously
earlier than the spring flights of the red-headed wood-
pecker and the flicker. Fluctuations in spring popu-
lations of the red-belly could be accounted for by
behavior other than migration, but students should
continue to look for the migration. As the red-belly
is increasing its populations northward, it is possibly
now evolving migratory behavior.

Distribution

There is evidence that the red-bellied woodpecker
has been slowly expanding its range northward in
Illinois for more than a century, and it has met with
increasing success in the past half century. Within
historic times it has been abundant in southern IIli-
nois (Ridgway 18816) with the population develop-
ing later in central and northern Illinois. Kennicott
(1853-1854) made no mention of the species in north-
eastern Illinois, where Nelson (1876-1877) called the
species rare in summer but not uncommon during
migration. Later, Woodruff (1907) considered it
only a rare migrant in the Chicago area. Farther
south the renowned oologist R. M. Barnes (1890) had
never found a red-bellied woodpecker nest in Mar-
shall County, and Loucks (1892 unpublished manu-
script) found the species rare in Peoria and Tazewell
counties. However, by 1905 Barnes (unpublished
note 1905) observed it increasing, and by 1912 the
species had become a common nester in the Illinois
River bottoms of Marshall County (Barnes 1912).
Away from the Illinois River in Logan County red-
bellies were still rare in 1918 (Du Bois 1918). The
range expansion appeared to progress even better on
the Mississippi than in the Illinois River valley, as
Schafer (1918) was seeing 6-10 red-bellies per day
during February and March, 1918, near Port Byron.
He also recorded red-bellies on 6 of 10 breeding bird
censuses between 1914 and 1923 (Table 7). At the
same latitude on the eastern side of the state at
Orland (Cook County), red-bellies were still uncom-
mon as late as 1947 (Coursen 1947) though they

21

were believed to be increasing (Moseley 1947). | Cook County began an accelerated increase in 1956.
Charles T. Clark (personal communication 1975) Our cross-country census of 1957-1958, which covered
noted that the red-bellied woodpecker population in 177 acres (16.2 miles) of forest in the two northern

Fig. 16.—A red-bellied woodpecker on a fallen tree at Allerton Park, Piatt County, Illinois, in October. Black middle rectrices
are missing, as the bird is in molt.

22

9 200 400 600 _ 000

= vA {
Dept of Geography — Univ of Illinois Tr wot ta a yo"

Fig. 17.-General distribution of the red-bellied woodpecker.
The range shown here may include large sections in which pop-
ulations of the species are thin or even absent because of the
nature of the terrain and lack of suitable habitat.

tiers of counties, did not intercept a red-belly within
the transect, but the census did not include extensive
riparian forest. There is a need for more recent pop-
ulation data on the red-belly in the north to compare
with those of Schafer (Table 7). The picture of the
red-bellied woodpecker’s range expansion in the north
appears to be one of surges and declines, with larger
populations along the major rivers. The population
is apparently still very thin in the north by compar-
ison with that of central Illinois.

The red-bellied woodpecker is an eastern U.S. spe-
cies (Fig. 17). In Illinois it probably nests in every
county though records are still lacking for many (Fig.
19). In addition to the records plotted in Fig. 19,
there is a definite nest record for Lake County for
which the specific locality was not given (Goelitz
1917).

Nesting Habitats and Populations

In summer the red-bellied woodpecker is essen-
tially a bird of the forest interior (Kendeigh 1944),
and Silloway (1922 unpublished manuscript) found
it most frequently in large trees of the interior. In

southern Illinois red-bellies make some use of shrub
habitat and pasture for foraging (Table 7). Red-
bellies do not generally inhabit residential areas in
summer (Ridgway 1887). They occupy both bottom-
land and upland forest, but most authors indicate
that bottomland is the preferred type (Nelson 1877;
Gates 1911; Kumlien & Hollister 1951). In east-central
Illinois Hess (1910) found red-bellies only in the
wilder timbered bottoms at a time when the species
was still expanding its population in that region.
Both Barnes (1912) and Yeager (1955) noted that
red-belly populations inerersed where timber was
flooded enough to kill trees.

At Morton Arboretum, apparently in upland hab-
itat, Swink (1959) found oaks, especially white oaks,
to be the most frequent perching sites for red-bellies.
By contrast, Kumlien & Hollister (1951) specifically
mentioned maple and ash, in preference to oak, as
habitat for red-bellies in heavy bottomland timber.

We measured summer populations of red-bellied
woodpeckers in five upland and eight bottomland
woods in southern Illinois in 1974 and again in 1975.
No correlation was found between numbers of these
birds and density or basal area of living or dead trees
of any genera or species with one exception. There
was a positive correlation between the number of red-
bellied woodpeckers per 100 acres in seven of the
bottomland woods and the Importance (Y) of maples
(r = 0.793, P < 0.02), particularly silver maples (r =
0.804, P < 0.02). The highest correlation among dif-
ferent size groups was for maples 10-18 inches DBH
(ry = 0.711, P < 0.05). We found no maples in one
bottomland woods, which had an average population
of red-bellied woodpeckers (see below). The red-belly
appears to occupy the maple-ash areas of bottomland
woods, while the red-head occupies the oak portions of
such woodlands. In a central Illinois woodland, Wil-
liams (1975) found that red-bellied woodpeckers spent
much time foraging in silver maples, whereas red-
heads in the same woodland spent much of their time
in oaks. Willson (1970) observed conflicts between
the two species in a central Illinois woodland and ob-
served that the red-head usually dominated.

The highest recorded Illinois population for a sig-
nificant habitat sample was 23 red-bellies per 100 acres
in a virgin floodplain elm-maple forest in Sangamon
County (Table 7). High populations in individual
forest tracts of 50 or more acres were 9-23 birds per
100 acres in both central and southern Illinois bottom-
land. Average populations from place to place and
year to year in bottomland forest were about 6 red-
bellies per 100 acres, and average populations in up-
lands were only slightly lower—4.5 per 100 acres.

Calef (1953a) and Stickel (1965) suggested that
red-bellies had notably large territories and home
ranges. In a mature bottomland forest in McLean
County Calef (1953a) measured five territories, which

23

20

10

224" 1224" 12 24° 12 24° 12 24° 12 24° 12 24 2 eee

305 FEB MAR APR MAY JUN JUL AUG SER OCT

CENTRAL
20

10

fe) & MIGRATING®

2/HR

BIRDS COUNTED PER DAY

24 I2 24 12 26 12 24. 12 242 2h 2 24 © 12 Dee

30 FEB MAR APR MAY JUN JUL AUG SEP OCT
SOUTH
20 fe)
O
(e)
(@)
10 ie)
4/HR
clo O O/aq

MIGRATING O

W224 °°12 24 12 2H 12 24 12 24 12 24 12 24 122k ieee
FEB MAR APR MAY JUN JUL AUG Sar OCT

Fig. 18—Egg-laying season and numbers of red-bellied woodpeckers seen in the spring, summer, and fall in the three regions of
Illinois. The spring and fall graph lines represent the higher count of each 4 days (1967-1970). Hollow circles represent counts
made in other years or by other observers. Shaded areas show the span of dates during which egg laying has been recorded.

24

TasLeE 7.—Breeding populations of red-bellied woodpeckers in various Illinois habitats.

‘ Birds per : Type of Region or
Habitat Acres 100 Acres* Years ie Grunts Reference
Oak-maple forest 55 ee 1927-1947 Map Champaign (C) Kendeigh 1944, 19486
avg 2.9)
Oak-maple forest 55 +18 1948-1974 Map Champaign (C) Kendeigh 19606; Kendeigh
(avg 7.9) & Edgington 1974
Oak-maple forest 64 6 1943 Map Champaign (C) Johnston 1947
Forest (all types, including edge) 214 4-5 1957-1958 Strip Central Graber & Graber 1963
(avg 4.7)
Forest (all types, including edge) 60 5 1907, 1909 Strip South Graber & Graber 1963
Forest (all types, including edge) 340 46 1957-1958 Strip South Graber & Graber 1963
(avg 5.0)
Mature upland forest 479 0-9 1974-1975 Strip South This paper
(avg 2.7)
Mature bottomland forest 913 0-11 1974-1975 Strip South This paper
(avg 4.0)
Virgin floodplain forest 77 23 1948 Map Sangamon (C) Snyder et al. 1948
Virgin floodplain forest 50 12 1947 Map Piatt (C) Fawver 19476
Mature bottomland forest 63 11 1950-1951 Map McLean (C) Calef 1953a
Grazed bottomland woods 53 7 1955 Map Macon (C) Chaniot & Kirby 19556
Forest (unspecified) 20 0-10 1914-1916 Rock Island (N) John J. Schafer (un-
(avg 3.3) published notes
1914-1923)
Forest (unspecified) 54 0-9 1917-1923 Rock Island (N) John J. Schafer (un-
(avg 4.3) published notes
1914-1923)
Upland second-growth oak-hickory 56 4-7 1941-1942, Map Sangamon (C) Robertson 19416,
(avg 4.8) 1944 1942b, 1944b
Upland second-growth oak-hickory 46 4 1948 Map Sangamon (C) Robertson & Snyder 1948
Upland oak-hickory 24 17 1967 Map Hancock (C) Franks & Martin 1967
Second-growth hardwood 15 13 1937-1938 Map Rock Island (N) Fawks 1937, 1938
Shrubby field and forest edge 60 2 1949 Map Richland (S) Stine 1949
Shrub area 39 5 1909 Strip South Graber & Graber 1963
Shrub area 129 0-3 1957-1958 Strip South Graber & Graber 1963
(avg 1.5)
Pasture 601 (4) ° 1907 Strip South Graber & Graber 1963
Pasture 120 0-1 1957-1958 Strip South Graber & Graber 1963
(avg 0.8)

2 All figures were converted to birds per 100 acres (number of territorial males or nests X 2).
>S refers to the southern region of Illinois, C to the central, and N to the northern region, as shown on winter distribution maps, e.g., Fig. 5.

¢ The plus symbol (+) indicates fewer than one bird per 100 acres.

ranged from 2.1 to 5.2 acres and averaged 3.5 acres.
In Piatt County Fawver (19476) measured three ter-
ritories, which averaged 6.1 acres in virgin floodplain
forest, and Allison (1947) méasured two territories,
which averaged 4.4 acres in mature upland forest.
There are no data on territory size for southern Ili-
nois. Reller (1972) suggested that red-bellies tend to
forage outside the woods in which they nest, perhaps
as a mechanism for reducing competition.

Bush (1934-1935) pointed out that an inverse re-
lationship exists between red-belly and red-head pop-
ulations after the nesting season (see Winter Popu-
lations), and the relationship of even the summer
populations shows something of the same tendency.
The ecological distribution of the two species in sum-
mer and winter shows that they tend to complement
one another. The broad occupancy of woody habitats
by red-heads in summer contrasts to the relatively
narrow occupancy of certain forests by the red-belly,
while in winter the situation is reversed, the red-belly
taking on a broad ecological distribution and the red-
head becoming much more restricted to forest. The

highest breeding population of red-bellies we found
in southern Illinois was in a forest that had no red-
heads. Even the geographic distribution of the two
populations tends toward segregation, with generally
more red-bellies in the southern part of the state, and
more red-heads in the northern part of Illinois. Will-
son (1970) has also observed segregation of the sexes,
during foraging, within a red-bellied woodpecker
population.

The published and unpublished data presently
available to us on nest sites include information on
only 31 nests of the red-belly, mainly in central Illi-
nois. Virtually all nests were in dead trees or stubs or
dead branches of live trees—notably oak, willow, elm,
maple, ash, cottonwood, poplar, sycamore, basswood,
and locust (species not specified). In east-central Illi-
nois red-bellies more often used dead limbs of live
trees, whereas red-heads nested in the trunks of dead
trees (Reller 1972). Heights (usually estimated) of
nests varied from 3 to 90 feet and averaged 32 feet.
Reller (1972) observed that nests in Piatt and Cham-
paign counties most often faced south or west.

25

RED -BELLIED WOODPECKER
BREEDING RECORDS

NESTS OR YOUNG

@ 1950 —
A 1900-1949

M@ BEFORE 1900

JUNE RECORDS

O 1950 —

A, 1900 — 1949

OD) BEFORE 1900

Fig. 19.—Distribution of breeding records of the red-bellied
woodpecker in Illinois. Hollow symbols represent birds seen or
heard during June.

Nesting Cycle

Most of what is known about the nesting cycle of
the red-bellied woodpecker in Illinois comes from a
study in southern Illinois by Stickel (1965) and a
study in central Illinois by Reller (1972). These
authors and Kilham (1958 and 1961) also discuss vo-
calization of the species.

Adult red-bellies separate after the breeding sea-
son, but remain somewhat territorial and often occupy
areas different from the nesting territory (Weise 1951;
Stickel 1965). In southern Illinois pairs may be
formed as early as January or as late as late April.
In central Illinois courtship activity involving agere-
gations of up to five birds and much calling and
chasing has been noted in the last half of February
and early March, and breeding territories appeared
to be established by the last of March (Allison 1947;
Fawver 1947a) .

Pair formation centered about the selection and
excavation of the nest cavity, in which the male took
the lead (Stickel 1965). At Carbondale the excava-

26

tion of cavities began in January and continued, off
and on, into April. In Piatt County Fawver (1947a)
observed the work of excavation during the first 3
weeks of April. The sizes of nest cavities of red-
bellied woodpeckers have not been recorded in
Illinois.

Bent (1939) gives egg dates for the red-belly in
Illinois from I April to 3 June (locality unspecified) .
In central Illinois egg laying occurs from at least 9
April through 23 June (Fig. 18). No nest is con-
structed within the cavity, the immaculate white eggs
being laid, one per day on consecutive days, on the
floor of the cavity. The red-belly, in contrast to the
flicker, is a determinant layer (Stickel 1965). Clutch-
size data representing 16 nests, mainly from old lit-
erature and museum records, showed this distribu-
tion: five eggs, 10 nests; four eggs, 4 nests; three eggs,
2 nests.

Stickel (1965) observed that incubation started
with the third egg laid, and required 11-12 days. In
case of nest failure, a second clutch was laid within
12 days, usually in a different cavity. Nestling life
lasted at least 22 days, and as long as 27 days, but
usually 26 days. Both sexes shared in the incubation
and care of the young but with considerable variation
from pair to pair. At night the male usually incu-
bated or guarded the nest (Stickel 1965). Exclusive
of cavity excavation, the cycle required about 41 days,
assuming the onset of incubation with the third egg,
as observed by Stickel (1965). The food of the nest-
lings was not specifically determined but included
both insects and fruit. At the Carbondale study area
Stickel (1965) observed the adults bringing food to
nestlings in different nests at average rates varying
from as few as four trips between | p.m. and 2 p.m.
to as many as 16 trips per hour around 9 a.m.—10 a.m.
The work of feeding was shared about equally by
the adults.

Quantitative data on nesting success have not been
recorded for any Illinois population of red-bellies. At
one nest Stickel (1962) found a large black rat snake
(Elaphe obsoleta) which had eaten nestlings and an
unhatched egg.

Fledglings at Carbondale remained near the nest
(within 100 feet) for at least 2 days, after which they
began to follow the parents. Juveniles appeared to
be independent about 6 weeks after fledging, when
they apparently left the area (Stickel 1965). Inten-
sive study of this species in Maryland by Kilham
(1961) revealed no evidence of double broodedness,
and single broods are probably the rule in Illinois
also.

Like other woodpeckers, red-bellies roost singly in
cavities, except for new fledglings, which roost in the
open and must learn the adult behavior. Again,
Stickel (1964) has provided most of the Illinois data
on the subject. He observed that, though there is a

surplus of cavities from the nesting season, both sexes
excavate additional cavities at other seasons. Such
roosting cavities are shallower than nest cavities. Nest
chambers were also used for roosting, particularly by
males. Birds change roosting cavities often and some-
times return to a formerly used cavity.

Competition for cavities in the nesting season has
not been considered a critical problem for the red-
belly in Illinois. Reller (1972) pointed out that
differences in nest-site selection have reduced com-
petition between red-heads and red-bellies. In the
south Stickel (1963) witnessed strife at a nest tree
between aggressive hairy woodpeckers and a pair of
red-bellies, which remained relatively passive toward
the hairies but vigorously attacked a flying squirrel
in the same tree. Stickel (1963) also observed aggres-
sion of red-bellies toward flickers at both nesting and
roosting cavities. In a screech owl nesting and roost-
ing box in Pope County, we found numerous feathers
of red-bellied woodpeckers, apparent victims of the
owl. Brown & Bellrose (1943) also recorded such
predation.

Fall Populations

After the breeding season, strife between red-
bellied and red-headed woodpeckers increases consid-
erably, as red-heads turn from more intraspecific ag-
gression to interspecific aggression directed especially
toward red-bellies (Reller 1972). Food is a probable
source of contention, as both species store mast. In
such encounters the red-head is almost always cdom-
inant (Ridgway 1889; Schafer 1918; Reller 1972) .

Beginning in late September, red-bellies, which
have been rather strictly forest birds during the
nesting season, expand their occupancy to other, more
open, habitats. Whether this change is a movement
of immatures, adults, or both is unknown. Nor is it
known to what extent the ecological shift entails more
than just local movement. At least a small part of
the movement appears to be migratory. We have
seen a few red-bellies flying with other diurnal mi-
grants along the Mississippi and Ohio valleys on
just three mornings between 30 September and 26
October (Fig. 18). The flight pattern and (appro-
priate southward) direction were the same as those
of blue jays, red-heads, flickers, and other species that
regularly migrate along these routes in fall. As we
have never seen more than four red-bellies per hour
on these routes, these migrations cannot account for
a sizeable population shift by the species. A red-
bellied woodpecker killed on a television tower near
Meredosia, Illinois, and found with over 100 spec-
imens of night migrants on the morning of 27 Sep-
tember 1972 (H. David Bohlen, personal communi-
cation) is the only indication we have of night
migration by the species. Stoddard & Norris (1967)
also reported a red-belly killed at a television tower

(in Florida), but they did not believe the incident
represented night migration.

In contrast to the spring populations of red-bellies,
fall populations show pronounced peaks (Fig. 18),
reflecting that the population is near its annual high
and that the species is increasingly conspicuous as
part of the population moves to more open habitats.

Our daily counts of birds in spring (March—May,
inclusive) and fall (August—-October) showed a ratio
of 1.0 red-belly in spring to 2.1 in fall for the state
as a whole, with very little difference in the ratios
from region to region. There are no data on fall age
ratios for the red-belly, as there are for the red-head,
with which to interpret the spring-fall ratios. The
fall-spring ratio for the red-belly is higher than that
of any other woodpecker in Illinois.

Winter Populations

The distribution of winter records for the red-
bellied woodpecker in Illinois is shown in Fig. 20.
The species probably occurs in every county in win-
ter, but published records are still lacking for several.

The fall dispersal of red-bellies that takes the
birds into habitats not generally occupied in summer
may also involve some extensive geographic displace-
ment, i.e., more than the migration that has been ob-
served. Kumlien & Hollister (1951) noted that in
1903 red-bellies appeared to be more common in
winter than in summer near the northern edge of the
species’ range. Similarly, Beal (1911) in central Iowa
found red-bellies ‘“‘abundant” in winter every year,
though he “never” saw one in the breeding season!
We have noted the same same phenomenon—red-
bellies apparently increasing disproportionately north-
ward in winter. Alfred Gross made the cross-country
censuses of 1907-1909, and we made them in 1957-
1958, and in neither case were red-bellied woodpeckers
detected within the northern Illinois census transects
in summer. In winter, however, red-bellies came within
the northern transects in both series of censuses
(Tables 7 and 8). The density of the winter popula-
tion of red-bellies increased greatly in the north be-
tween 1907 (1 bird per 100 acres in forest) and 1957—
1958 (9.5 per 100 acres). The cumulative Christmas
counts of red-bellies (Fig. 21) also show notable up-
ward surges in northern Illinois, 1915-1925 and 1954—
1959, and in central Illinois, 1919-1939 and 1954—
1959, while the southern Illinois counts have remained
relatively stable. Recent (1965-1975) annual variation
in the Christmas counts has ranged from about 2
percent to 46 percent per year and averaged 20-21
percent in northern and southern Illinois but only
8 percent in the central region. On the long-term
average, it took 3.6 party hours to find a red-belly on
the northern Christmas counts, 1.2 hours on the cen-
tral counts, and 1.0 hour on the southern counts.

The population dynamics of the red-bellied wood-

27

RED -BELLIED WOODPECKER
WINTER RECORDS

DEC. 15 -FEB.1
et.
” SS | STEPHENSON | wont gago | ra Qe )) Ue
@ 1950 ——— sail wo, e
| | \
A 1900-— 1949 ——4 2) om | @
Tesi ? ce | i
HM BEFORE 1900 we pA

Fig. 20.—Distribution of winter records of the red-bellied
woodpecker in Illinois. Heavy horizontal lines separate the
three regions of the state (north, central, and south) referred
to in the text.

pecker in Illinois are puzzling. From population den-
sity figures and habitat acreage figures, we estimated
the June population of red-bellies in the state to be
about 190,000 adult birds in 1957-1958, with about
150,000 in the southern region, 40,000 in the central
region, and an almost negligible population (under
2,500) in northern Illinois. In winter (January) the
state population jumped to about 515,000 (2.7 times
the June number), with about 360,000 in southern
Illinois (2.4 times the June number) , 99,000 in cen-
tral Illinois (2.5 times the June number), and an
incredible 55,000 in northern Illinois (22.0 times the
population of June). In more recent censuses in
southern Illinois (1973-1975), the number of winter
red-bellied woodpeckers was 2-3 times that found in
summer in the same woodlands. To some extent the
increase in winter reflects the increased conspicuous-
ness of red-bellies in open field habitats and in forests
with the foliage gone, but there is no reason to believe
that conspicuousness is increased more in. northern

28

Illinois than in the other regions. The winter data
for central and southern Illinois do not indicate any
major exodus of red-bellies. Better population data
are needed for both summer and winter populations,
especially in the north, to answer at least these ques-
tions: (1) Is the great increase in numbers of red-
bellies in winter real? (2) If so, why are the increases
not comparable in central and northern Illinois?
(3) Where does the excess winter population in the
north come from?

Although the red-belly expands its occupancy of
habitats in winter, forest remains an important hab-
itat (Table 8). Winter population densities of red-
bellies were higher in bottomland than in upland
forest, as they were in summer (Tables 7 and 8). In
southern Illinois Ferry (1907a) observed that red-
bellies favored tall softwood trees of the river bottoms,
where there was a large proportion of decayed tree
trunks.

In five upland woods in southern Illinois in the
winters of 1973-1975 we found positive correlations
between the densities of red-belly populations and
the Importance (Y) of hackberry, the Importance of
ash, and high basal area, particularly of large trees.
For hackberry the correlation was 0.906 (P= < 0.02);
for ash, 0.969 (P= < 0.01); for total basal area,
0.866 (P= < 0.05); and for the ratio of the basal
area of large trees to total basal area, 0.972 (P=
< 0.01). There was a negative correlation between
the numbers of red-bellied woodpeckers and the Im-
portance of oaks (r = — 0.810, P= 0.05) and of hick-
ories (r = — 0.876, P= < 0.05).

In eight bottomland woods in southern Illinois in
the winter there was some correlation between red-

2.0
5

CENTRAL

BIRDS PER PARTY HOUR

1910 1920 1930 1940 1950 1960 41970
(JANUARY )

Fig. 21.—Red-bellied woodpeckers seen per party hour on Au-
dubon Christmas counts in the three regions of Illinois. Each
point represents a 5-year average except that annual variation
is shown between 1965 and 1975 for the north and south regions.

Tas_eE 8.—Winter populations of red-bellied woodpeckers in various Illinois habitats.

. Birds per Years Type of Region or
Habitat oon 100 fees (January) Gace Coane EG IESEAES
Suburban woodlot 205 Gi) 10 1968-1972 Map Lake (N) Miller & Miller 1970, 1972
(avg 5.0)
Urban residential 164 0.6 1976 Strip North This paper
Urban residential 191 0 1976 Strip Central This paper
Urban residential 191 5 1976 Strip South This paper
Oak-maple forest 55 0-16 1925-1975 Map Champaign (C) Kendeigh 1944; Kendeigh
(avg 5.5) et al. 1957
Oak-maple forest 55 0-4 1925-1936 Map Champaign (C) Kendeigh 1944
(avg 1.5)
Oak-maple forest 55 2-5 1938-1949 Map Champaign (C) Kendeigh 1944, 1948a, 1949
(avg 4.4)
Oak-maple forest 55 2-16 1950-1975 Map Champaign (C) Kendeigh et al. 1951, 1957
(avg 7.4)
Grazed bottomland woods 53 4-11 1955, 1957 Map Macon (C) Chaniot & Kirby 1955a;
(avg 7.5) Kirby & Chaniot 1957
Bottomland forest 50 (+) 1951 Map Cook (N) Montague 1951
Mature bottomland forest 1,398 0-25 1974-1976 Strip South This paper
(avg 9.6)
Mature upland forest 712 1-17 1974-1976 Strip South This paper
(avg 6.3)
Forest (all types, including edge) 46 4-9 1940-1941 Map Piatt (C) Johnston 1942
(avg 6.5)
Forest (all types, including edge) 65 1 1907 Strip North Graber & Graber 1963
Forest (all types, including edge) 45 ARI 1957-1958 Strip North Graber & Graber 1963
(avg 9.5)
Forest (all types, including edge) 50 2 1907 Strip Central Graber & Graber 1963
Forest (all types, including edge) 152 4-10 1957-1958 Strip Central Graber & Graber 1963
(avg 7.9)
Forest (all types, including edge) 241 5 1907 Strip South Graber & Graber 1963
Forest (all types, including edge) 211 7-12 1957-1958 Strip South Graber & Graber 1963
(avg 9.5)
Shrub habitat, including edge shrub 74 Pee) 1957-1958 Strip Central Graber & Graber 1963
(avg 5.4)
Shrub habitat, including edge shrub 33 3 1907 Strip South Graber & Graber 1963
Shrub habitat, including edge shrub 101 15-18 1957-1958 Strip South Graber & Graber 1963
(avg 16.8)
Shrubby field and forest edge 85 (+) -1 1955-1956 Map Richland (S) Shaw & Stine 1955;
Shaw et al. 1956
Shrubby field 40 (+) -10 1958-1965, Map Lawrence (S) Scherer & Shaw 1960;
(avg 4.4) 1968 Shaw et al. 1968
Pasture 440 0 1907 Strip North Graber & Graber 1963
Pasture 83 1 1957 Strip North Graber & Graber 1963
Pasture 343 2 1907 Strip Central Graber & Graber 1963
Pasture 156 0-2 1957-1958 Strip Central Graber & Graber 1963
(avg 1.3)
Pasture 208 1 1907 Strip South Graber & Graber 1963
Pasture 93 0 1957-1958 Strip South Graber & Graber 1963
Fallow fields 114 1 1907 Strip South Graber & Graber 1963
Fallow fields 103 2 1957-1958 Strip South Graber & Graber 1963
Cornfields 60 3 1907 Strip South Graber & Graber 1963
Cornfields 277 1 1957-1958 Strip South Graber & Graber 1963

8 The plus symbol (+) indicates fewer than one bird per 100 acres.

> N refers to the northern region of Illinois, C to the central, and S to the southern region, as shown on winter distribution maps, e.g., Fig. 5.

bellied woodpecker numbers and the Importance of
hackberry (r = 0.730, P = < 0.05). Likewise, there was
some correlation between the density of red-bellied
woodpeckers and the basal area ratio (basal area
of large trees to total basal area) (r=0.701, P=
< 0.05). In the bottomland forest interior, red-bellies
apparently seek the larger trees, especially maples and
hackberries. The species can thus to some extent
avoid the red-headed woodpecker, which predom-

inates in the oaks in the bottoms. The presence of
over 35 red-heads per 100 acres in bottomland woods
seems to depress the red-bellied woodpecker popula-
tion (Fig. 22). In four bottomland woods with over
35 red-heads per 100 acres, the red-bellied population
was 3.5-5.5 birds per 100 acres. In four bottomland
woods with red-headed woodpecker numbers of less
than 35 per 100 acres, the red-bellied woodpecker
population was 17.5-18 birds per 100 acres. In all

29

RED-BELLIED
WOODPECKERS |

bh
co

bh
mn

po
eo a

—
i)

ho
>)

[oe]

(op)

RED-HEADED
WOODPECKERS

tS

NUMBER OF RED-BELLIED WOODPECKERS PER 100 ACRES
NUMBER OF RED - HEADED WOODPECKERS PER 100 ACRES

Avie Bis (Cc SDR bs ies GH
LOCALITIES

Fig. 22.—Inverse relationship between winter populations of
red-headed and red-bellied woodpeckers. Points on the dash
line represent numbers of red-bellied woodpeckers in eight bot-
tomland woods in southern Illinois, identified in the introduc-
tion. Points on the solid line represent numbers of red-headed
woodpeckers in the same woods.

eight woodlands there was a negative correlation
(r=— 0.556, P=>0.10) between average popula-
tions of these two species for 3 years. In individual
woodlands the negative correlation between these
two populations in the 3 years was —0.781 (P=
> 0.10); — 0.843 (P= > 0.10); — 0.916 (P= < 0.10);
— 0.987 (P= < 0.02); — 1.00 (P= < 0.001). In two
woodlands there was no correlation and in one there
was a positive correlation (0.991, P= < 0.01). The
very large old trees and the generic composition
(many maples and hackberries) may have allowed
this latter woodland to support high populations of
both species (2-year average: 34 red-heads and 18
red-bellies per 100 acres) .

Red-bellies are generally tree gleaners (Reller
1972), foraging on trunks and limbs of trees, and

30

their presence in such open-field habitats as cornfields,
fallow fields, and pastures in winter (Table 8) indi-
cates some ground or near-the-ground foraging not
mentioned in the Illinois literature.

Food Habits

Beal (1911), referring not specifically to Illinois,
found the red-bellied woodpecker’s food during the
year to be about 31 percent animal matter and 69
percent vegetable. Of all food types, mast (acorns,
beechnuts, hazelnuts, and pecans) was most impor-
tant, constituting about 31 percent of all food and a
much larger portion (67 percent in November) in
fall and winter. We have seen red-bellies working on
pecans in late September in the Mississippi Valley of
Union County. Fruit, especially wild fruit, was also
important throughout the year, but varied from a
low in April (7.5 percent of the diet) to a high in
August (64 percent) .

Of animal food, beetles, most notably weevils and ©
wood-boring species, were a consistent part of the
diet, as were ants. Orthopterans—grasshoppers, crick-
ets, and egg cases of cockroaches—were important
throughout the year, though more so in summer.

There are few specific Illinois observations on the
food. Ridgway (1889) believed the red-belly to be
a pest in orchards because of its fondness for apples.
Red-bellies eat corn, but not in economically signif-
icant amounts. Red-bellies have been observed feed-
ing on chokecherries in southern Illinois (Ferry
19076) and sassafras fruit in central Illinois (Allison
1947). The red-belly is also well known at feeders,
taking suet, cheese, and grain, including sunflower
seeds (Vredenburgh 1905; Schafer 1918; Cone 1956).
Southern (1966) observed red-bellies feeding on dead
gizzard shads in winter in northwestern Illinois.

Longevity

There are, to our knowledge, only two longevity
records for the red-bellied woodpecker in Illinois,
both around 5-6 years. A bird banded in 1966 south
of McLeansboro, Illinois, was found dead 5 years
and 8 months later in the same locality (computer
printout from U.S. Fish and Wildlife Service Bird
Banding Office 1972). Another bird banded in 1924
at Kansas, Illinois, was retrapped in the same place
nearly 5 years later (Cooke 1937).

Specimen Data

Red-bellied woodpecker specimens from TIllinois,
of which we have examined 49 (28 males, 21 females),
are for the most part separable from comparably
plumaged specimens of the nominate race from South
Carolina and Georgia, which have a darker appear-
ance, especially on the back and rump. We consider
all the Illinois specimens to represent Centurus caro-
linus zebra though there is great variation in back

'

Taste 9.—Measurements of Illinois specimens of red-bellied woodpeckers, excluding obviously worn, molting, and ju-

venile specimens.

Num-
Y ber Culmen (from Naris)
oan Months oh Sex Wing (Chord) in mm Tail Length in mm inmm
inois : — —— — Se a E
DEBE Range Mean sD Range Mean sD Range Mean sD
mens
North and Central Dec.—Feb. 6 M 126-133 130.1 2.62 76-85 79.1 3.12
South Dec.—Jan. 8 M 125-134 130.5 3.20 76-83 79.6 2.62 arn a6 506
State Mar-Apr. 25 M 125-134 130.2 2.66 75-85 79.4 2.65 24-28" 25.8 1.11
OctFeb.
State Oct.—Mar. 20 F 121-134 127.5 3.05 23-258 24.3 0.95

*« Culmen measurements from only seven males and seven females.

color (black-to-white ratio), with about one-fourth
of them showing coloration somewhat intermediate
toward C. c. carolinus. ‘There was no consistent color
or size difference between specimens from northern
and central Illinois and those from southern Illinois
(Table 9). Females averaged slightly smaller than
males in all measurements.

Weights of males from northern and central Ilh-
nois were 74.3 and 80.6 grams for April specimens,
83.6 for a February specimen, and 91.8 for a Novem-
ber specimen. Weights of female specimens from cen-
tral Illinois were 78.6 grams (February specimen) ,
and 73.9 and 74.2 grams (November specimens) .

RED-HEADED WOODPECKER

(Melanerpes erythrocephalus)
(Fig. 23, 24, and 25)
Spring Migration

The impressive diurnal migrations of red-headed
woodpeckers often seen in Illinois in fall have appar-
ently never been recorded in spring. Most of the
spring migration may be nocturnal. We have heard
red-headed woodpeckers calling at night relatively
rarely compared with the frequency with which we
have heard the flicker. In east-central Illinois we have
heard what we believed to be red-heads in migration
on nights between 24 April and 7 May between 8:50
p-m. and 3:20 am. CST. Musselman’s (1931) state-
ment that red-heads “appeared over night” on 15
April 1930 also suggests night migration.

Because red-heads winter in some years in all
parts of the state, the onset of spring migration is
often obscured by the presence of wintering birds.
Published spring arrival dates for the state range
from mid-February (Beal 1886; Strode 1892; Gault
1901; Musselman 1932) to early May (Walter & Wal-
ter 1904). Red-head populations exhibit great annual
variation in behavior, and this range of arrival dates
is probably truly representative of the species, depend-
ing upon the year cited. The range of arrival dates
is so variable that the spring migration of red-heads
is not predictable with any accuracy in contrast to
those of most migrant species.

75-86 78.5

The arrival dates most frequently cited in the
Illinois literature fall in the period 23-30 April with
no consistent difference between regions. There are
also indications of migration waves in the periods
1-10 and 20-30 March and 5-15 April.

Our counts (Fig. 26) showed notable population
changes in late March and early April in southern
and central Hlinois, and in late April and early May
in central and northern Illinois. High spring pop-
ulations came 7—23 April in southern Illinois, 29
April-7 May in central Illinois, and 9-13 May in
northern Illinois (Fig. 26). Cooke (1943) reported
on a bird banded in Highland Park on 20 May 1940,
which was captured alive at Estelline, South Dakota,
about 3 weeks later on 10 June—seemingly a very
late migrant.

Distribution

The red-headed woodpecker is a species mainly
of the eastern and central United States (Fig. 25).
In Illinois red-heads probably nest in every county,
though the breeding distribution is still incompletely
known (Fig. 27).

Nesting Habitats and Populations

In the breeding season, the red-headed woodpecker
is a savannah or forest-edge species with generally low
populations in forests (Table 10, disregarding samples
under 30 acres) unless the forests become opened up
by some such calamity as fire, disease, or wind dam-
age. Thus, Butler (1897) pointed out that red-head
populations become very high at times of ‘‘deaden-
ings,” i.e., when trees are killed in epidemic propor-
tions. Similarly, Yeager’s (1949) study of flooded
bottomlands showed that as flooding killed large num-
bers of trees, the woodpecker population—partic-
ularly the red-head population—surged upward. Mus-
selman (1930) observed that red-heads were attracted
to an area of fire-killed oaks. The relationships be-
tween red-head populations and dead trees is shown
by the studies of Kendeigh and his students on Tre-
lease Woods (Champaign County), where red-head
numbers climbed dramatically as American elms (a
dominant species) died from elm diseases on a mas-

31

ptr
hy.

Fig. 23.—Juvenile red-headed woodpecker at Allerton Park, Piatt County, in October. A gray head and black bars on wings are
characteristic of the juvenile plumage.

sive scale and opened up the forest (Kendeigh &
Brewer 1956; Kendeigh & Brooks 1963b). Dutch elm
disease, because of its wide distribution, has almost
certainly been responsible for an increase in the state’s
red-head population in the past 20 years. As natural
succession fills in the gaps where large elms fell, the
red-head population is likely to decline again.

Red-heads nest in both upland and lowland hab-
itats (Table 10). Our June censuses of 13 woodlands
(5 upland, 8 bottomland) in southern Illinois indi-
cate a strong preference by red-heads for bottomland
woods in that region. In only one upland woods
were any red-heads seen, and this particular upland
woods adjoined a bottomland that had a high breed-
ing population (over six birds per 100 acres) .

Age of stand, basal area or density of all trees or

32

any size class of trees, diversity, Importance of any
species or genus (or any size class thereof) in the
eight bottomland woods analyzed vegetatively could
not be correlated with numbers of red-headed wood-
peckers present in June. Five genera of trees (woody
plants over 4 inches DBH) made up 75 percent of
the Importance of trees in each of six woodlands hav-
ing red-heads. These genera were Quercus (oaks),
Carya (hickories), Celtis (hackberries), Ulmus (elms),
and Acer (maples). One woodland (E) with a pop-
ulation of two to three birds per 100 acres consisted
simply of 75 percent oak, 23 percent hickory, and the
remainder ash, elm, and persimmon. The two bot-
tomland woods without red-heads had less than 70
percent (Importance) of the five genera of trees men-
tioned above, and less than 45 percent of their compo-

Fig. 24—Adult red-headed woodpecker with food for its
young at its nest hole 11 miles east of Havana, Mason County,
llinois, in early July.

= 3
ay =
5 i ian , 10°}
£ sets bs
feo ay YY
’ ayd ‘
a so
& sas Sales
eee ae i. > re
Ee Se oe ee US eR :
= v = pe
x4 hy lg Cee wo}
0 = moe fy,
» tar ~
hese: ‘ .

Loe

+f

'. Woodpecker
‘Y Ul AR “A foe

~ Ranges
F<] BREEDING

== winter

Oost of Geography - ron . — ~ 2 oN A

Fig. 25.—General distribution of the red-headed woodpecker.
The range shown here may include large sections in which
there are few, if any, red-headed woodpeckers because of the
nature of the terrain and lack of suitable habitat.

sition was oak-hickory-hackberry-elm. The amount of
forest edge and open areas within woods—providing
in effect forest edge—are probably important to the
red-head. In the eight bottomland woods studied, the
highest populations (9-12 birds per 100 acres, 2-year
average) occurred in woods that had a large amount
of edge and internal openings either from fallen trees
or because of the presence of streams and oxbows
within them. The simple (in diversity) woodland
(E) mentioned above had many irregular open areas
within it because of a fire that had occurred some 10
years earlier. Williams (1975) found that red-headed
woodpeckers in a central Illinois woodland spent most
of their time foraging in oaks and dead trees in open
areas in the woodland.

Red-headed woodpeckers are tolerant of humans.
Ridgway (1887) considered the red-head by far the
most numerous breeding woodpecker in the city of
Mt. Carmel, and there are many old nest records for
the species in cities throughout the state. More re-
cently, however, urban populations of red-heads have
been poor. The strip-censuses of 1957-1958 showed
breeding populations of only two birds per 100 acres
in southern Illinois towns (Table 10), while numbers

33

20 10 20 30 9 IE) aS) 9 IKE} =) 10
FEB MAR APR MAY
80
60
CENTRAL
«a

BIRDS COUNTED PER DAY
Nn
°

20 10 20 30 9 19 29 9 19 29 10
FEB MAR APR MAY

20 10 20 30 i9 29 19
FEB MAR APR MAY

29 10

20 30
JUN JUL AUG SEP OcT

%168/hr
Migrating

30° 10 20 30° 9 19 29 10 20 10 20 30
JUL AUG Bayar SEP ae i 120/hr
ae 2

A TY ae
/ 3)
re) ° <e

° °
e) CENTRAL
fe}

20 30 lo 20 30! 9 19 29 10 20 30 10 30
JUL AUG SEP a
SOUTH
Migrating—14/hr

10 20 30 19 29

Fig. 26.—Egg-laying and migration seasons of the red-headed woodpecker in different regions of Illinois. Spring and fall graph

lines show the higher daily count of each 4 days (1967-1970) .

Hollow circles represent counts made in other years or by other ob-

servers. Dark dots (southern region) represent isolated counts made in 1967. Shaded areas show the span of dates during which

egg laying has been recorded.

in central and northern Illinois cities were too low
to detect in our samples. In urban areas red-heads
are in the starling’s stronghold and often fail in com-
petition with that species (Moseley 1947; Polder 1963).
As red-heads nest in. shrub areas (Table 10) and
other woody habitats more open than forest, the sig-
nificance of dead trees to this bird may be primarily
related to increased sunlight or visibility in the hab-
itat. Nest sites of red-heads are often in dead trees.
Published nest-site data for 47 red-head nests in north-
ern and central Illinois showed about 80 percent to
be in dead trees, usually in the trunks. Some of the
nests reported in live trees may have been in dead
branches. Of 33 nests for. which we have data, 45
percent were in elms and 24 percent were in oaks.

34

From dead tree to utility pole would seem but
a small change. W. S. Brenneman (personal com-
munication) of the Illinois Power Company has
studied woodpecker damage to utility poles and found
the red-head to be the species by far most often in-
volved in such damage.

Nest heights varied from 4 to 40 feet, with no
significant mode, and averaged about 20 feet. In
Champaign and Piatt counties, Reller (1972) noted
that red-head nests faced predominantly south and
west.

Reller (1972) also observed that in summer red-
heads foraged to a large extent on the ground. The
statewide strip censuses of 1907-1909 and 1957-1958
showed that red-heads were often found in grasslands

) 1950—
\ 1900 — 1949
J] BEFORE 1900

1ESTS OR YOUNG
» 1950 —
4 1900 — 1949

1 BEFORE 1900

JUNE RECORDS

RED-HEADED WOODPECKER
BREEDING RECORDS

Oo] 0 10%10 0 1190
(Soi@Titi sey
LL ex re)

2.9! ora

0c!

Fig. 27.—Distribition of breeding records of the red-headed
woodpecker in Illinois. Hollow symbols represent birds seen or
heard in June.

of all types in densities high enough (three to four
per 100 acres) to indicate that this is an important
foraging habitat for the species.

The population trend for the red-headed wood-
pecker since the turn of the century had been down-
ward until recent years. We estimated the June pop-
ulation of breeding adults in Illinois to be about
1,270,000 in 1909 and only 115,000—-134,000 in 1957—
1958 (Graber & Graber 1963). Since then, coinciding
with the great die-off of elms in the state’s forests,
red-head numbers have increased, but the level of the
present state population is unknown. Our census
figures for some southern forest areas (Table 10)
provide an indication of the increase. In 1957-1958
red-heads were not detected in the forest transects, but
in 1974 we recorded an average density of three birds
per 100 acres in mature bottomland forest and of four
birds per 100 acres in 1975.

The causes of the decline in the red-headed wood-
pecker population before the elm epidemic can only
be surmised. White settlement of Illinois in the 18th
and 19th centuries greatly reduced forest acreage but
increased edge habitats that favored red-heads.

Since about 1920 habitats have changed increas-
ingly to block forms while edge habitats have de-
clined (Graber & Graber 1963). The two woodpecker
species (red-head and flicker) that particularly oc-
cupied the edge underwent about the same decline
(roughly 90 percent) between 1907 and 1957. A
second factor that affected both species adversely in
this period was the starling with its incredible pop-
ulation increase in the 20th century and its ability
to compete with native species, particularly in man-
aged habitats. The recent decline in the red-headed
woodpecker’s populations apparently ended when the
elm epidemics created much new natural habitat. In
recent years large reservoir construction has flooded
extensive areas of lowland forest, killing the trees and
creating more habitat for red-heads. The durability
of this habitat is probably relatively short. Yeager’s
(1949) data show about one-fourth of the trees down
in 8 years from the onset of flooding.

Eifrig (1937 and 1938) stated that red-head num-
bers were declining because of the automobile. He
observed that red-heads were sometimes hit by cars
as the birds picked up insects from the road. Red-
heads do appear to show special susceptibility to this
type of mortality (Flint 1926 and 1934-1935; Blocher
1927; Komarek & Wright 1929; Starrett 1938) .

Few Illinois species seem as argumentative as the
red-head. Much of the time they appear to be bicker-
ing among themselves or with other species. This
intra- and interspecific aggression is exhibited both
in and out of the breeding season (Cooke 1916;
Schafer 1917; Ridgway 1920; Cone 1956; Willson
1970; Reller 1972). Hess (1910) suspected an inverse
relationship between red-head and flicker populations
in central Illinois, and in southern Illinois Bush
(1934-1935) detected an inverse relationship between
red-head and red-bellied woodpecker populations in
winter. Reller (1972), Willson (1970), and Schafer
(1917) observed that aggression was particularly keen
between red-heads and red-bellied woodpeckers. Red-
head strife has also extended to flickers, pileateds,
downies, and other woodpeckers, starlings, brown
creepers, house wrens, white-breasted nuthatches, blue
jays, house sparrows, squirrels, and other species (E.
E. 1885; Cooke 1885b and 1916; Butcher 1896; Field
1917; Moseley 1917; Ridgway 1920; Reller 1972;
Moseley 1947). Red-heads also have a bad reputation
for attacking other birds’ nests, breaking and some-
times eating eggs (and even killing fledglings) , mainly
of cavity-nesters, e.g., chickadees, bluebirds, cliff swal-
lows, and wood ducks, but also even of domestic
chickens and of wood pewees (Willard 1896; Schafer
1920 and 1923; Frank Bellrose personal communi-
cation) .

Nesting Cycle

A number of banding records indicate homing in
Illinois red-head populations, and summer-banded

35

Taste 10.—Breeding populations of red-headed woodpeckers in various Illinois habitats.

Habitat Acres bays ca Years mis hes ce Reference
Suburban residential 8 25 1916 Nest Richland (S) ® Cooke 1916
Urban residential 235 0 1958 Strip North & Central Graber & Graber 1963
Urban residential 98 2 1958 Strip South Graber & Graber 1963
Modified woodland (human housing) 28 14 1937 Nest Lake (N) Beecher 1942
Unmodified woodland 27 15 1937 Nest Lake (N) Beecher 1942
Oak-maple forest 55 0-18 1927-1943 Map Champaign (C) Kendeigh 1944
(avg 6.0)
Oak-maple forest 64 3 1947 Map Champaign (C) Johnston 1947
Oak-maple forest edge 1.25 0-46 1944-1975 Map Champaign (C) Kendeigh 19486;
miles* (avg 13.7) © Kendeigh &
Brooks 19656
Forest (all types, including edge) 177 1-6 1957-1958 Strip North Graber & Graber 1963
(avg 4.0)
Forest (all types, including edge) 214 3-6 1957-1958 Strip Central Graber & Graber 1963
(avg 4.7)
Forest (all types, including edge) 60 5-13 1907, 1909 Strip South Graber & Graber 1963
(avg 10.0)
Forest (all types, including edge) 340 0 1957-1958 Strip South Graber & Graber 1963
Grazed bottomland woods 53 4 1955 Map Macon (C) Chaniot & Kirby 1955b
Mature bottomland forest 1,077 0-18 1973-1975 Strip South This paper
(avg 3.4)
Mature upland forest 479 0-1 1974-1975 Strip South This paper
(avg 0.4)
Upland second-growth oak-hickory 56 4-11 1941-1942, Map Sangamon (C) Robertson 19416, 1942b,
(avg 5.9) 1944 1944b
Second-growth hardwoods 15 27 1937-1938 Map Rock Island (N) Fawks 1937, 1938
Woods (unspecified) 20 10-20 1914-1916 Nest Rock Island (N) J.J. Schafer (unpub-
(avg 16.7) lished notes 1914-1923)
Woods (unspecified) 54 7-23 1917-1923 Nest Rock Island (N) J.J. Schafer (unpub-
(avg 16.3) lished notes 1914-1923)
Savannah 23 18 1957-1958 Strip North & Central This paper
Orchard 45 45 1907, 1909 Strip South Graber & Graber 1963
(avg 4.4)
Orchard 78 0 1957-1958 Strip South Graber & Graber 1963
Late shrub 21 10 1966 Map Vermilion (C) Karr 1968
Shrub area 50 3-7 1957-1958 Strip Central Graber & Graber 1963
(avg 4.0)
Shrub area 56 28 1907, 1909 Strip South Graber & Graber 1963
Shrub area 129 0 1957-1958 Strip South Graber & Graber 1963
Swampy prairie 64-67 9-19 1941-1942, Map Sangamon (C) Robertson 1941a, 1942a,
(avg 14.3) 1944 1944a
Pasture 193 3 1909 Strip North Graber & Graber 1963
Pasture 279 0-1 1957-1958 Strip North Graber & Graber 1963
(avg 0.4)
Pasture 441 4-7 1907, 1909 Strip Central Graber & Graber 1963
(avg 5.9)
Pasture 171 0 1957-1958 Strip Central Graber & Graber 1963
Pasture 882 2-4 1907, 1909 Strip South Graber & Graber 1963
(avg 2.6)
Pasture 120 0 1957-1958 Strip South Graber & Graber 1963

a All figures were converted to birds per 100 acres (territorial males or nests X 2).
> S refers to the southern region of Illinois, C to the central, and N to the northern region, as shown on the winter distribution maps, e.g., Fig. 5.

© These entries are miles of forest edge and birds per mile of edge.

birds—presumably local breeders—have returned as
early as 17 April (Lincoln 1927) .

Little has been recorded on the red-head’s nesting
cycle in Illinois, and virtually nothing on its nesting
in the southern region. In northern Illinois Gault
(unpublished notes 1889) observed nest excavation in
progress on 25 April, and in central Illinois Mussel-
man (1937) observed mating of red-heads on 5 May.

As is typical of woodpeckers, no nest is constructed,
and the white eggs are merely laid on the floor of

36

the cavity, often on wood chips from the excavation.
Polder (1963) observed the excavation of a nest cavity
in 2 days by a pair of red-heads. Sizes of natural
cavities used as red-head nests have not been mea-
sured in Illinois. Ford (1939) gave these nest-box
dimensions for this species: floor, 6 x 6 inches; depth,
12-15 inches; height of entrance above floor, 9-12
inches; diameter of hole, 2 inches. Gault (unpub-
lished notes 1877) measured one cavity that was 9
inches deep. Red-heads have used nest boxes in IIli-

nois, and Musselman (1934 and 1935) recorded about
a 5 percent frequency of occupation of bluebird boxes
by red-heads. Frank Bellrose and Robert Crompton
(personal communication) have never found red-
headed woodpeckers nesting in wood duck boxes
though flickers commonly do so.

Egg laying begins at least as early as 6 May in
southern Illinois, 7 May in central Illinois, and 11
May in northern Illinois, and occurs at least as late
as 7 July in the north (Fig. 26). Laying, especially in
the south, probably begins earlier than present records
show. Data on clutch sizes are mainly from old lit-
erature or old museum records. The average of 30
clutches from northern and central Illinois was 4.7
eggs, with the frequency distribution being: 6 eggs,
21 percent; 5 eggs, 43 percent; 4 eggs, 27 percent; and
3 eggs, 10 percent.

Neither the incubation period nor the duration
of nestling life have been measured in any Illinois
population of red-heads. Observations by Kyler (1927)
indicate that nestling life may exceed 3 weeks, but
it has not been precisely measured.

There are no measurements of nesting success for
any Illinois population of red-heads. The earliest we
have seen young out of the nest was 18 June in the
south and 7 July in central Illinois, where fledglings
are frequently observed in the 2nd week of July.

Red-headed woodpeckers sometimes raise two
broods. Reller (1972) observed that at least 3 pairs,
of 15 under observation in central Illinois, nested a
second time while still caring for the first broods
fledged.

Age Ratios

The distinctive and relatively long-lived juvenile
plumage of the red-headed woodpecker (Fig. 23) pro-
vides a potentially useful indicator of productivity in
this species. Kyler (1927) hand reared three young
red-heads and found that red began to appear on
their heads about 10 weeks after hatching. During
our censuses, when we were able to see red-heads
clearly enough to age them, we recorded adults and
juveniles, or immatures, separately. The ratios of
the two age groups are shown in Table 11. As the

first birds fledged in June and July, the proportion
of young was naturally low—only 8 percent by 20
July in west-central Illinois. There was a consistent,
progressive increase in the percentage of young from
summer into fall (Table 11). We observed a ratio
of 0.9 young per adult among red-heads migrating
along the Mississippi River in a large migration of
these birds on 21 September.

Note also (Table 11) that while the percentage
of young increases later in the season, the total num-
ber of birds seen declines, suggesting that adults tend
to precede the young in migration. Nelson (1876—
1877) believed that it was young birds which tended
to winter in Illinois. We have often seen immatures,
with dark or partly dark heads and juvenile wing
patterns, in January, but we have seen only one bird
with that combination of characters as late as 9 April.
Immatures with partly red heads are seen commonly
in early September.

Fall Migration

The diurnal migration of red-headed woodpeckers
in Illinois is sometimes conspicuous, with 100 or more
birds passing a given point in an hour. The birds
fly silently, singly, and in loose, somewhat linear
groups, generally fewer than 20 birds at a time with
5- to 15-minute gaps between groups. They fly at
heights ranging from 50 to 600 feet or more above
local terrain. The birds follow essentially the same
flight line, passing over or parallel to distinctive top-
ographic features, most notably the scarp of a flood-
plain. Often up to 15 or more other species are in-
volved in these flights, most often blue jays, whose
numbers generally far exceed the numbers of red-
heads and other species. Though the migration
routes of the red-head and jay do coincide in places,
it is not known whether the routes are the same
throughout the state. We have seen both species mi-
grating along the Mississippi, Illinois, and Ohio rivers.
We have not witnessed such migrations on other
waterways, and there are no published observations
of the migration elsewhere in the state though it is
to be expected on other major streams and perhaps
along the Lake Michigan shore. The directions of

Taste 11.—Age ratios of red-headed woodpeckers in central Illinois (1969) and northern Illinois (1968) .

West-Central East-Central Northwestern
vhs Total Birds Percent Total Birds Percent Total Birds Percent
Aged Immature Aged Immature Aged Immature

July 11-20 65 8
July 21-31 172 30 +90 ae
August 1-14 168 54 187 25 ion a
August 15-31 119 50 193 40 202 24
September 1-30 54 61 171 44 150 47
October 1-31 5 . 53 57 8 30

Total 583 604 360

Mean (after July) 54 38 33

37

the fall flights are generally downstream, south or
west of south, but eastward (Widmann 1907) and
southeastward (Cooke 1888) flights have been ob-
served at St. Louis. Weber (1966) witnessed an ap-
parent reverse (northward) fall migration up the
Mississippi at Keokuk. We have seen red-heads mi-
grating under both clear and cloudy skies, including
overcast, and with southerly and northerly winds and
in calms. The relationship (if any) of these flights
to frontal weather systems is unkrfown.

The highest flight density we have recorded was
168 red-heads per hour on 21 September 1968 near
Thomson, Illinois, on the Mississippi, but Widmann
(1907) ounted 284 per hour crossing the Mississippi
at St. Luuis on 15 September 1884. More frequently
we have observed densities of 80-120 red-heads per
hour in September and October on the Mississippi
and Illinois rivers (Fig. 26). The highest flight den-
sity we have seen on the Ohio River was only 14 red-
heads per hour. Our observations have all been made
from the Illinois side of the rivers. Such migrations
occur on both sides as well as over the Mississippi
River, but there are no data on where the river mi-
grants originate their flights and little on their sea-
sonal, annual, or geographic variation. We have usu-
ally seen the flights between 6:00 and 11:00 a.m. CST,
but the large flight seen by Weber was mostly in the
afternoon (11:30-4:30 p.m.). These migrations are
heaviest in September and October. They begin at
least by 28 August (Graber 1962; Nolan 1957a) and
extend to at least 26 October.

Such migrations occur every year, but not every
day of the season. Many days in September and Octo-
ber we have looked for the flights in vain. Although
such migrations are impressive, they do not seem to
account for even a large part of the massive popula-
tion shift of red-heads that occurs every year between
summer and winter at Illinois latitudes. We have ob-
served what appeared to be long-distance daytime
flights of single red-heads across country where there
was no obvious association with distinctive topogra-
phy. The headings were southeast in east-central IIli-
nois and southwest in west-central Illinois. Such
flights may merely represent the origins of the flights
along the rivers where the birds become concentrated.

Besides these diurnal flights, red-heads also migrate
at night, but the relative volume of diurnal versus
nocturnal migration is unknown. Ridgway’s (1881a)
father heard red-heads migrating at night over Wa-
bash County in early October 1879. Nearly all of the
local population vanished concomitantly with that
migration. We have also heard what we believed to
be red-heads calling at night, apparently in migration
in east-central Illinois on a few nights between 7 Sep-
tember and 22 October between the hours of 8:00 p.m.
and 4:00 a.m. CST. The presence of red-heads among
the night migrants killed at television towers in IIli-
nois 9-29 September is also indicative of night migra-

38

tion, but the species is relatively rare as a tower cas-
ualty—only 5 red-heads among over 12,000 birds
identified from tower kills in Illinois.

The ratio between the numbers of birds counted
in spring and those counted in fall is particularly in-
teresting for the red-headed woodpecker because of the
age-ratio data we have for this species. If the spring
population is the adult breeding population and the
fall population is the surviving adult population plus
the surviving young, then we may expect some con-
sistent relationship between the age ratios and the
spring-fall ratios. In northwestern Illinois we saw 1.5
red-heads in fall (August—October, inclusive) for every
one seen in spring (March—May, inclusive). As the
age ratio for that region was 0.5 young per adult, the
fall numbers were about as expected. In east-central
Illinois the spring-fall ratio was 1.0:1.6, and the age
ratio was 0.6 young per adult, thus in line with the
fall ratio. In west-central Illinois, where the age ratio
was the highest—1.2 young per adult—the fall ratio
was lowest, 1.0 in spring to 1.2 in fall. We cannot ex-
plain the discrepancy. In the south the spring-fall
ratio was 1.0:1.1; our age-ratio data in the south were
too scanty to evaluate.

Winter Populations

Red-headed woodpeckers have been found in all
regions of the state in winter (Fig. 28), but such a
statement tends to obscure the fact that massive
changes occur every year in the red-head population
between summer and winter. Fall migration shifts the
population southward, generally leaving few birds in
the northern region and much reduced numbers in
the central region, whereas the population in southern
Illinois may be greatly increased over the summer
level. Mast production of oaks, beeches, and other
food plants have a pronounced effect on the regular
migrations of red-heads in fall and winter, and vari-
ation in the winter population is extreme. In some
winters red-heads remain even in the north in large
numbers (Schafer 1922; Fig. 29) .

There is some evidence that the winter popula-
tions of red-heads have been extending their range
northward. ‘The great annual variation in winter
populations makes this difficult to prove, but several
observations, including the Christmas counts, suggest
it. During his life time, Holland (1931) saw a def-
inite increase in the winter population at the latitude
of Knox County. Dr. S. C. Kendeigh’s censuses of
Trelease Woods in Champaign County also show a
trend toward an increased winter population there.
The extensive cross-country censuses of Alfred Gross
and Howard Ray in the winter of 1906-1907 revealed
no red-heads in the central region of the state al-
though red-heads were found on both of our (1957
and 1958) cross-country winter censuses (Graber &
Graber 1963). If there is a progressive change in

RED-HEADED WOODPECKER
WINTER RECORDS
DEC. 15 -FEB.1

* .o,

20 MBss | sreeminson mmmtsago, F

@ 1950-
A 1900- 1949

@ BEFORE 1900

ete fr a Tar

ae

Fig. 28.—Distribution of winter records of the red-headed
woodpecker in Illinois. Heavy horizontal lines separate the
three regions (north, central, and south) referred to in the text.

range, it is very erratic, with notable regressions some
years (Fig. 29).

As in summer, red-headed woodpecker populations
in southern Illinois were censused in eight bottom-
land and five upland forests in the winters of 1973-
1976. When all of the bottomland woods were con-
sidered, no significant correlations were found. How-
ever, when the two woods having the highest winter
populations and the two woods having the lowest
winter populations were examined, a few correlations
were found. There was a positive correlation between
the number of red-heads and oaks of acorn-bearing
size, over 10 inches DBH (r = 0.909, P = < 0.05 for
1975 and r = 0.961, P= < 0.01 for 1976). These same
four woodlands also showed a correlation between
number of red-heads and the Importance of pin oak
(r = 0.839, P = < 0.10 in 1975 and r = 0.930, P =
< 0.05 in 1976).

Holland (1931) observed that the same oak woods
were chosen for winter resorts by red-heads year after
year in Knox County. Other observers (Musselman

1930; Mooney 1932; Willson 1970) have called atten-
tion to the red-head’s affinity for oaks (and acorns) in
winter. Willson (1970) and Reller (1972) suggest
that maples also are important in the winter habitat.

In uplands the only wintering red-heads not found
in woods adjoining bottomland woods were in a tract
which had very heavy beech mast. In the following
2 years there was little or no beech mast in this woods,
and no red-heads were found there. The average
number of winter red-heads in bottomland woods (35
per 100 acres) was about four times the number
(9 per 100 acres) in upland woods for the same 3-year
period. There is an indication of an alternate high-
low population fluctuation in our data. In 1973-1974
there were 20 red-heads per 100 acres (in all woods,
upland and bottomland) ; in 1974-1975 there were 31
red-heads per 100 acres: in 1975-1976, 21 per 100
acres; and 58 per 100 acres in 1976-1977. This pat-
tern of high red-head populations in the odd-numeral
years is In agreement with the observations of Ander-
son (1965 and 1967), who noted the alternate-year
cycle in Missouri, where the population was relatively
low in (January) 1964, high in 1965, low again in
1966. The alternate-year pattern does not appear with
any constancy in the Christmas counts. In the central
region there are several-year runs of alternate high
and low counts, but more often in the south there are
2, or sometimes 3, relatively high years followed by a
drop (Fig. 29). We have found no statistically signif-
icant correlation between the annual counts in differ-
ent regions of the state. The 5-year averages of the
Chirstmas counts for the three regions of the state sug-
gest an inverse relationship between winter popula-
tions of red-heads in southern versus central and/or

4.0 NORTH
CENTRAL
SOUTH

a eee ate

BIRDS PER PARTY HOUR

1900 ©=6.:110 20 30 40 50 60 1970

(JANUARY)

Fig. 29.—Red-headed woodpeckers seen per party hour on
Audubon Christmas counts in the three regions of Illinois.
Each point represents a 5-year average.

39

northern Illinois (Fig. 29). Annual variation in
Christmas counts in recent years (1965-1975) for the
red-head ranged from about 3 to 160 percent per year
(excluding one change of 555 percent in the north,
1974-1975) and averaged about 45 percent per year
in southern Illinois, 57 percent in central Illinois, and
43 percent in the north. :

The statewide censuses of 1957-1958 show how
varied the winter populations may be (see also Table
12). In the winter of 1956-1957 we estimated the
state population of red-heads to be 92,000 (72 percent
in the southern region) , but the next winter the state
population was 424,000 (98 percent in the south).
This population appears to be an exception to the
odd-year highs of the 1960’s and 1970’s mentioned
above. The sources of these winter birds in Illinois
are unknown.

Besides the great population shift to the south in
winter, red-heads move from the more open forest
edge and savannah habitats to forest proper almost ex-
clusively. This change may be less a change in the
bird than a change in the habitat, i.e., an opening of
the forest from the loss of foliage, the forest thus be-
coming a well-lighted, more open habitat similar to
that which the red-head occupies in summer. How-
ever, Reller (1972) observed a definite change in for-
aging by red-heads from ground foraging in summer
to tree trunk and limb foraging in winter.

Food Habits

There are numerous brief observations on the food
habits of the red-headed woodpecker in Illinois, but

there are no comprehensive studies on the subject.
Rice (1946) examined six specimens from Champaign
County, and found that vegetable matter made up 70
percent of the food in winter, 45-50 percent in spring
and fall, but was absent from the diet in summer,
when insects, especially Lepidoptera and Coleoptera,
comprised most of the food. Coleoptera were impor-
tant in the diet (15-20 percent of the food) at all sea-
sons, and Hymenoptera (25 percent) were especially
important in fall, less so (10 percent) in summer.
Forbes’ (1882a and 1882b) study of four specimens
taken in late May at a Tazewell County orchard heav-
ily infested with canker worms showed that 80 percent
of the red-heads’ food was insects, mainly (64 percent)
Coleoptera (ground beetles and scarabs) plus 15 per-
cent Lepidoptera (canker worms), and 20 percent
vegetable matter (corn). Red-heads commonly forage
by “flycatching,” but what they catch has not been
recorded.

Among all the Illinois references to mast consump-
tion by red-heads, little specific data are provided.
Musselman (personal communication, 1962) and Smith
& DuMont (1945b) have called attention to the im-
portance of pin oak fruit in the fall and winter diet
of red-heads in the Mississippi valley. Musselman also
mentions red oaks as being attractive to red-heads
(Mumford 1959a) , and we have often seen them work-
ing on white oak acorns. However, the relative values
to red-heads of the various species of acorns have not
been studied. Also not yet studied is the red-head’s
use of acorns versus beechnuts or other mast.

Red-heads have been seen storing acorns in their

TABLE 12.—Winter populations of the red-headed woodpecker in various Illinois habitats.

. Birds per Years Type of Region or
EASES ERE 100 Acres (January) Census County ce

Urban residential 355 0 1976 Strip North & Central This paper

Urban residential 191 0-1 1976 Strip South This paper
(avg 0.5)

Oak-maple forest 55 0-42 1954-1962 Map Champaign (C)* Kendeigh 1960a; Kendeigh
(avg 12.5) & Brooks 1962

Oak-maple forest edge 1.25 0-23» 1963-1975 Map Champaign (C) Kendeigh & Brooks 1964a;

miles” (avg 6.8) Kendeigh & Clemans 1970

Forest (all types, including edge) 46 0-6 1940-1941 Map Piatt (C) Johnston 1942
(avg 3.3)

Forest (all types, including edge) 152 1-3 1957-1958 Strip Central Graber & Graber 1963
(avg 2.0)

Forest (all types, including edge) 241 1 1907 Strip South Graber & Graber 1963

Forest (all types, including edge) 211 2-15 1957-1958 Strip South Graber & Graber 1963
(avg 8.1)

Mature upland forest 772 0-33 1974-1976 Strip South This paper
(avg 8.2)

Mature bottomland forest 1,398 4-89 1974-1976 Strip South This paper
(avg 33.7)

Grazed bottomland forest 53 0-4 1955-1957 Map Macon (C) Chaniot & Kirby 1955a,
(avg 1.3) 1956; Kirby & Chaniot 1957

Shrubby field 40 0-7 1958-1965, Map Lawrence (S) Scherer et al. 1959; Shaw

1968 et al. 1968

*C refers to the central region of Illinois and S to the southern region, as shown on winter distribution maps, e.g., Fig. 5.
> These entries are miles of forest edge and birds per mile of edge.

40

own nest cavities (Jones 1933) and under the bark
and in crevices of trees (Sanborn 1921). Moseley
(1917) witnessed similar storage of suet, which may
be used to attract these woodpeckers (Brintnall 1918;
Williams 1924) although Schafer (1918) found cracked
walnuts a more effective attractant. In South Dakota
Winkenwerder (1902) reported red-heads storing live
grasshoppers in tree crevices. The only reference on
the amount of food materials stored is an anonymous
(1922) observation of a red-head that worked through-
out the winter at Moline, putting about 400 acorns
and pieces of oak bark into two wren houses. The
cache, which was never used, weighed 1234 ounces at
the end of the winter.

Formerly, at least, red-heads were sometimes con-
sidered pests on cultivated fruit, notably strawberries,
cherries, pears, and apples (Gault, unpublished notes
1895; Le Baron 1855; Kinney 1868). Lyon (1923)
found apples to be a good bait for trapping red-heads,
and they also feed on mulberries in season. Southern
(1966) observed one feeding on a dead gizzard shad
in winter.

Beal’s (1911) study of the red-headed woodpecker’s
food in North America showed the species to be much
more of a vegetarian than most woodpeckers—animal
matter constituting about 54 percent of the diet and
vegetable matter 66 percent. Beetles, including most
notably large adult predaceous ground beetles (Ca-
rabidae) and tiger beetles (Cicindelidae), made up
about 19 percent of the food. The red-head was also
less of a wood driller than other woodpeckers, taking
few wood-boring larvae. Ants comprised about 5 per-
cent of the year’s food, going as high as 14 percent in
June and July. Red-heads ate large numbers of grass-
hoppers in August (21 percent of the diet), and less
in September (9 percent). Also in August and Sep-
tember grain, notably corn, became a significant part
(22 and 19 percent, respectively) of the red-head’s
diet. Small fruits (blackberries, cherries, etc.) aver-
aged about 3 percent of the year’s food, going as high
as 17 percent in July. Especially from October to Jan-
uary, mast (mainly acorns) became the predominant
food, averaging about 55 percent of the diet.

Mortality and Longevity

In addition to the losses due to automobiles, men-
tioned earlier in this paper, red-heads are also lost be-
cause of pesticides. Montgomery (1956) found one
dead after DDT was sprayed on trees to control Dutch
elm disease, and a nest failed when both adults suc-
cumed to a tree spray (Mumford 1961). Red-heads
were 3 of 259 prey items in screech owl boxes (Brown
& Bellrose 1943) .

There are few published Illinois records of lon-
gevity and none of more than 2 years (Lincoln 1927;
Cooke 1937). Subfossil remains of red-headed wood-

peckers were found at the Modoc Rock Shelter and
were aged 3,000-8,000 B.C. (Parmalee 1959).

LEWIS’ WOODPECKER
(Asyndesmus lewis)

There are two sight records of Lewis’ woodpecker
for the state, one on 24 May and 26 May 1923 in
Roger’s Park (Evanston) on the north side of Chicago
(Hine 1924) and one on 14 May 1932 at Argo (Sum-
mit) on the south side of Chicago (Ford 1956) .

YELLOW-BELLIED SAPSUCKER
(Sphyrapicus varius)
(Fig. 80 and 31)

Spring Migration

Yellow-bellied sapsuckers may be found in all parts
of Illinois in winter, but the spring migration be-
comes conspicuous as the numbers of sapsuckers in-
crease in March and April (Fig. 32). The migration
has apparentely never been witnessed directly in
spring, and may be strictly, or at least largely, noc-
turnal (see under Fall Migration). A large kill of
141 sapsuckers in or along the beaches of Lake Mich-
igan on the night of 16 April 1960 may have occurred
while the birds were in night migration (Segal 1960) .
A similar incident involving only two sapsuckers near
Waukegan on 2 May was reported by Boulton &
Pitelka (1937) .

February records refer most often to the winter
population, but apparent migration waves may be de-
tected as early as 21 February, particularly in southern
Illinois. More typically the first waves are noted after
15 March, with noticeable influxes occurring between
21 and 31 March (Oberholser 1928; Smith 1930).
Musselman (1932) recorded one large influx on 14
March at Quincy. Peak numbers of sapsuckers come
even later, in early and mid-April, and most of them
have passed north of Illinois by the end of April (Fig.
32). In some years, particularly in east-central and
northeastern Illinois, large numbers of transient sap-
suckers appear. Beal (1886) recorded such an inva-
sion on 9 April 1886, the birds remaining for 3 days.
Except for such invasions, sapsuckers are usually seen
singly or in twos, and generally one sees not more
than five per day.

In southern Illinois very few sapsuckers linger past
April, the latest date on record being 5 May (Ober-
holser 1928; George 1968). In central and northern
Illinois, where a very thin and spotty breeding popu-
lation survives, a few sapsuckers stay on through the
summer, but nearly all sapsuckers seen in Illinois are
transients, which pass through central and northern
Illinois by mid-May (Fig. 32).

4]

Benjamin Gault’s unpublished records from 1875 tend to predominate in numbers in the early spring
to 1927 in northeastern Illinois indicate that males migration through the first week in April after which

Fig. 30.—Immature yellow-bellied sapsucker. Photo taken by J. W. Graber in Busey Woods (Urbana, Illinois) in April. Inset
shows adult yellow-bellied sapsucker. Photo by Dr. W. J. Beecher, Chicago Academy of Sciences.

42

. Ranges
fi] BREEDING

= wInTeR

Fig. 31—General distribution of the yellow-bellied sapsucker.
The range shown here may include large sections in which pop-
ulations of the species are thin or absent because of the nature
of the terrain and lack of suitable habitat.

females become more common and predominate in
the later migrations after 20 April. The transients
show a broad tolerance for woody habitats, occurring
in urban areas as well as in extensive forests. Actual
measurements of transient populations of sapsuckers
are lacking for any habitat.

Distribution

In eastern North America the yellow-bellied sap-
sucker nests in the northern USA and Canada, but the
breeding range extends well south in the western USA
as well as in the mountains of the east (Fig. 31).

In Illinois the breeding range is very spotty (Fig.
33) and probably now restricted to northern and cen-
tral Illinois though suitable looking habitat is plenti-
ful in southern Illinois. The old record for St. Louis
(Fig. 33) is that of Hurter (1884). The fact that
neither Ridgway (1889) in southeastern Illinois nor
Widmann (1907) in the St. Louis area knew the sap-
sucker as a breeding species in their respective areas
implies that the species was not a common nester in
the south even in the last century. The significance of
a sight record for a sapsucker at Horseshoe Lake (Alex-

ander County), 13 August 1932 (Gower 1933) is
uncertain.

Nesting Habitats and Populations

No breeding population of sapsuckers has been
measured systematically in Illinois. Petersen’s (1956)
discovery of three active nests in Henderson County
in 1 day (19 June 1955) and DuMont’s (1936) refer-
ence to the species on the Des Moines River across the
Mississippi from Illinois indicate that there are mea-
surable populations in or near the Mississippi valley.
In the Illinois valley Loucks (1891) considered the
species rare at Peoria, but a short distance to the
north, in Marshall County, Barnes (1890) called it
“tolerably common.”

The preferred nesting habitat is lowland forest
subject to flooding (Barnes 1890; DuMont 1936; Peter-
sen 1956). There is also an indication of sapsuckers
nesting in urban residential habitat (Roberts 1922) .

No territories have been measured in any habitat.

Nesting Cycle

Nesting of the sapsucker has not been studied in
Illinois. Near Peoria Silloway (unpublished manu-
script 1923) observed what he called nuptial activities
of sapsuckers (possibly transients) on 6 April, noting
that the birds were very noisy. The call most often
heard in Illinois is a distinctive catlike squeal.

Nest cavities in Henderson County were 30-45 feet
high in living oaks (Petersen 1956). In Marshall
County R. M. Barnes found nests in both dead and
live willows, the nest height varying from 12 to 20 feet
(Chicago Museum of Natural History oological col-
lection). Loucks (unpublished manuscript 1891) de-
scribes a nest 15 feet up in a dead tree in Tazewell
County.

Old literature and museum records indicate that
egg laying by sapsuckers in northern Illinois extends
from at least 20 April to 3 June (see also Bent 1939) .
The same sources indicated that clutch size varies
usually from four to six eggs. Barnes considered the
clutch of eight eggs that he found near Lacon to be
very exceptional (Chicago Museum of Natural His-
tory oological collection) .

There are no data on nesting success in Illinois.

Fall Migration

Aside from the very slim breeding population, sap-
suckers do not appear in Illinois again until Septem-
ber. Benjamin Gault’s long-term records show that
sapsuckers are rarely seen before 10 September even
in northern Illinois (see Schafer 1925; Blake & Smith
1941 for early records). ‘They increase conspicuously
in northern and central Illinois between 15 and 24
September, and most of them have passed through the
north by 12 October and through central Illinois by
20 October (Fig. 32). Our earliest fall record for the

43

12 24
MAR

12 24
APR

12 24
30 FEB

20

ay
(on)

Ul

BIRDS COUNTED PER DAY

12 24
MAR

12 24

APR MAY

10

12 24
FEB

12 24
MAR

12 24
APR

12 24
MAY

SOUTH

NORTH

12 24
JUN

12 24
JUL

12 24
SEP ©

12 24

AUG OCT

12 24
JUN

12 24
JUL

12 24
SEP

12 24

AUG OCT

3/HR,
re)

12 24
JUN

12 24
JUL

12 24
AUG

12 24
Slee

12 24
OCT

Fig. 32.—Egg-laying and migration seasons of the yellow-bellied sapsucker in different regions of Illinois. Spring and fall graph
lines show the higher daily count of each 4 days (1967-1970). The dashed graph line (north) represents the cumulative counts of
sapsuckers made by Benjamin T. Gault between 1875 and 1927, mainly in Du Page County. Hollow circles represent counts made in
other years or by other observers. The shaded area (north only) shows the span of dates during which egg laying has been recorded.

south was 17 September. Because the migrant popu-
lation of sapsuckers in the south appears low (Fig.
32) and the winter population there is relatively high,
the end of the fall migration in the south is obscured.
Peak numbers of transient sapsuckers have been seen
20 September-8 October in northern Illinois, 28 Sep-
tember—18 October in central Illinois, and 8-28 Octo-
ber in southern Illinois. Balch (1970) observed a
large wave of sapsuckers at Waukegan 22 September
1970.

The data on bird kills at television towers in cen-
tral Illinois also show the migration pattern of sap-

44

suckers there. The kill data span August-November
1955-1972, during which period about 12,000 dead
birds (all species) were picked up and identified. All
(43) of the sapsuckers were killed between 23 Septem-
ber and 7 October -(Brewer & Ellis 1958; Petersen
1959) , a period in which sapsuckers constituted about
1 percent of all (4,400) birds killed. Nearly all of
these sapsucker specimens, adults and immatures, were
still clearly in the molt on the head and anterior
body. Graber’s (1968) view that few sapsuckers are
killed compared with the number seen is yet to be
verified.

MIGRATING

@ 1950 — —t5/
bce | ogre

_A 1900-1949 a
ale cee

M@ BEFORE 1900 wale

YELLOW-BELLIED SAPSUCKER

BREEDING RECORDS

NESTS OR YOUNG

|

| [ee
20 DAMESS | STEPHENSON | wnnteago) F |

JUNE - JULY RECORDS

O 1950— te eae Le r= |
X,econouy) seyeron J THEME |e ce ay
A 1900 - 1949 ro a wl eee
MASON as & ; +) Hq
O BEFORE 1900 EZ pgeie=at {ome nm
cs ss we] L arr | ‘
Tes Ao | ie '
Li — froverme § 4 coaan
ee. ——j crmstun | . pieae es |
] T1 | iN] Ast

GREENE

| L____s sneer

Zope Nuscoushe | wontcoutny |

wer |

SNe: Seno

J RICHLAND leer

WASHINGTON
JEFFERSON

Fig. 33.—Distribution of breeding records of the yellow-
bellied sapsucker in Illinois.

Most of the migration must be nocturnal. Besides
the evidence of the tower kills, we have heard what
we believed to be sapsuckers uttering the character-
istic cat call while migrating at night (8:20 p.m—
5:20 a.m.) over east-central Illinois between 12 Septem-
ber and 14 October. We have seen diurnal migration
of sapsuckers but once—l October 1972 (morning),
the birds flying with jays and other woodpeckers down
the Ohio valley in Pope County.

Our counts showed a ratio of 1.0 sapsucker in
spring to 1.8 in fall statewide, but there was a pro-
gressive decline in the ratio from north (1.0 to 2.9) to
central (1.0 to 1.9) to south (1.0 to 1.3). The age
ratio in a small sample (22) of specimens from a cen-
tral Illinois tower kill was 1.0 adult to 1.75 immatures.

Winter Populations

Yellow-bellied sapsuckers have been found in all
regions of the state in winter (Fig. 34), but the pop-
ulation declines progressively from south to north, as
the Christmas count data clearly show (Fig. 35). The
occurrence of sapsuckers in the north in winter is

irregular (Duncan 1937), in some years falling vir-
tually to zero (Fig. 35), but annual variation is great
in all regions. The long-term averages of Christmas
count data show that it has taken about 92 party
hours of observation to find a sapsucker in the north,
versus 45 hours in central Illinois, and 17 in the south.

Judging from population densities, we conclude
that bottomland forest and residential areas are the
favorite winter habitats. The highest population we
have measured in a tract at least 40 acres in size was
about 12 sapsuckers per 100 acres in a mature bottom-
land forest in Alexander County in January 1975, a
year with notably high populations in the south (Fig.
35). Average populations were 1.6 sapsuckers per
100 acres in both mature bottomland and urban res-
idential habitat in the south, but only 0.4 per 100
acres in mature upland oak-hickory. Shrub habitat is
also used in the south (Shaw 1961; Table 13).

Prior to about 1939 the Christmas counts had too
few knowledgeable participants in Illinois to detect
sapsuckers with any regularity The record since then

YELLOW-BELLIED SAPSUCKER
WINTER RECORDS

DEC. 15 -FEB.1
iO cla
@ 1950- SES Sasha | a
cm | gs ecliaal seg
1900 — 1949 ea CAT
YO eee el smell
M BEFORE 1900 All Seeclle

a J Ee es —s!
ga

€

Fig. 34.—Distribution of winter records of the yellow-bellied
sapsucker in Illinois. Heavy horizontal lines separate the three
regions (north, central, and south) referred to in the text.

45

12 1948
e 1962
e ~ SOUTH
pli) 1949 (INDIVIDUAL YEARS)
=
S 08
ee
= SOUTH
0G
(ee
Lid
fol
wm
= 04
a ih
/ \
(02

CENTRAL

—

-_—-——
_

-

\
\— NORTH

(JANUARY)

Fig. 35.—Yellow-bellied sapsuckers seen per party hour on
Audubon Christmas counts in the three regions of Illinois. Each
point represents a 5-year average. The dash line shows annual
fluctuations in the southern Illinois counts in recent years. Dots
designate high counts in 1948, 1949, and 1962.

shows an upward trend in winter numbers in more
recent years (Fig. 35) though the highest count was
in the southern region in January 1948, a high also
noted by Cunningham (1948). The southern counts
for 1949 and 1962 were also exceptionally high (Fig.
35). Extreme annual variation in the counts makes
any conclusion tenuous, particularly as the aggressive-
ness of Christmas count participants in finding birds

has also been increasing over the years. The counts
show some tendency toward alternate year highs and
lows (Fig. 35), but the pattern is far from consistent.
The early cross-country censuses of Alfred Gross and
Howard Ray, conducted in southern Illinois in Feb-
ruary 1907 may also indicate that the sapsucker win-
ter population is increasing. They detected no sap-
suckers in 241 acres of forest, whereas we found an
average of about two sapsuckers per 100 acres in 1957—
1958 (Table 13). However, there is now no way we
can determine whether 1907 was a “low” year for
sapsuckers.

Sapsuckers were about four times as numerous in
bottomland woods as in upland woods in southern
Illinois. They prefer larger trees (r = 0.924, P= <
0.001 between numbers of trees over 22 inches DBH
and numbers of sapsuckers). The sapsucker popula-
tion proportionately increased in woods with greater
numbers of large trees (Fig. 36). There was also a
negative correlation (r = —0.804, P = < 0.01) be-
tween sapsucker numbers and the percentage of the
total basal area of a forest made up of small trees,
4-10 inches DBH.

The composition of bottomland woodlands fav-
ored by wintering sapsuckers reflected their food pref-
erences. Maples usually constitute more than 15 per-
cent in Importance (Y), elms more than 10 percent,
and oaks less than 25 percent. There were positive
correlations between the numbers of sapsuckers and
the Importance of pecan (r = 0.617, P = < 0.10) ; pe-
can and sugar maple (the latter not very numerous in
bottomland) (r = 0.820, P = < 0.01); pecan, sugar
maple, and tulip tree (r = 0.733, P = < 0.05); and
elms (r = 0.604, P =< 0.10). There was a negative
correlation for the Importance of oaks (r= —0.601,
P= < 0.10). Sapsuckers seldom drill the species of
oaks that are dominants in these woodlands. The sap-
sucker apparently shares the winter habitat of the
red-bellied woodpecker and downy woodpecker, as its
numbers correlate with numbers of those species (r =

0.736 and 0.742, respectively, P = < 0.05).

Tae 13.—Winter populations of the yellow-bellied sapsucker in various Illinois habitats.

3 Birds per Years Type of Region or
SATIN ORE 100 nee (January) Cas County BGT
Urban residential 164 0.6 1976 Strip North This paper
Urban residential 19] 1.6 1976 Strip South This paper
Suburban woodlot 20 O- (+) * 1968-1972 Map Lake (N) ” Miller & Miller 1968
Forest (all types, including edge) 241 0 1907 Strip South Graber & Graber 1963
Forest (all types, including edge) 211 1-4 1957-1958 Strip South Graber & Graber 1963
(avg 2.4)
Mature bottomland forest 1,398 0-12 1974-1976 Strip South This paper
(avg 1.6)
Mature upland forest 772 0-6 1974-1976 Strip South This paper
(avg 0.4)
Shrubby field 40 0-2 1958-1965, Map Lawrence (S) Shaw 1958, 1961
1968

@ The plus symbol (+) indicates fewer than one bird per 100 acres.

DN refers to the northern region of Illinois and S to the southern region, as shown on winter distribution maps, e.g., Fig. 5.

46

5-8 BIRDS

PER 100 Acres

20

="
uw

1-2 BIRDS
PER 100 Acres

—_

-] BIRD PER
100 acres

LARGE TREES PER ACRE

IP ne 1S D B G Cc UA

Fig. 36.—Relationship of yellow-bellied sapsuckers to large
trees (trees over 22 inches DBH). Bars represent eight different
bottomland woods in southern Illinois.

The upland woods in which wintering sapsuckers
were found in southern Illinois were adjacent to bot-
tomland woods and had more maples (mostly sugar
maples) than had upland woods in which no sap-
suckers were found (the Importance of maples was
greater than 9 percent in upland woods with sap-
suckers present) .

Food Habits

Though there are a number of references to the
presence of sapsuckers at winter feeding stations (Beall
1908; Smith & DuMont 19456; Fawks 1966 and 1970) ,
few tell what food was taken by the species. Mussel-
man (1933) mentions sapsuckers eating suet. Sap-
suckers have also been observed feeding on the fruit
of hawthorn (Crataegus sp.) , ‘matrimony vine” (Du-
Mont 1947a), and “‘winterberry” (Link 1940) .

Most of the Illinois literature on the food of sap-
suckers concerns tree drilling (Fig. 37). Though other
woodpeckers feed to some extent on cambium and
sap, the sapsucker clearly lives up to its name when it
comes to this method of foraging. Beal (1911) found
that the sapsucker’s food through the year was about
49 percent animal, and 51 percent vegetable, making
it the only woodpecker he studied that eats more veg-
etable than animal matter. Ants were apparently the
favorite animal food, constituting about 34 percent of
the diet and being taken throughout the year but
most commonly from May to August. Various beetles
were also important in the diet, making up about 5
percent of the food.

The common types of vegetable food for sapsuck-
ers were fruit (28 percent of the diet) and cambium

(16.5 percent). The fruit, notably a variety of wild
berries, was taken mainly in fall (71 percent of the

Fig. 37.—Yellow-belied sapsucker drill holes on a mature
sugar maple, a favorite food source of this bird.

47

food in November). Cambium was eaten most in win-
ter and spring, constituting about 49 percent of the
food in April and only 1.5 percent in November. In-
teresting is the observation of Southern (1966) of a
sapsucker feeding on dead gizzard shad in winter.

In his extensive investigation McAtee (1911) found
that the sapsucker attacked no fewer than 246 species
of native North American trees, 61 species of native
vines, and 31 introduced trees.

TABLE 14.-Woody plants* drilled by the yellow-bellied sapsucker in Illinois.

a

In Illinois we have found sapsucker drillings i in st
species of woody plants, 72 of which are listed in Ta.
ble 14. In southern Illinois woodlands the species
most often showing sapsucker drillings (excluding datat
from small samples) are overcup oak, slash pine, tulipi
tree, pecan, red cedar, and silver and sugar maples:
The high incidence of sapsucker drillings in overcup!
oak (42.8 percent) is surprising, since all other oaks
(660 trees) observed in the south had a combined:

— |
North East-Central South |
Species Number Percent Number Percent Number Percent Site
Examined Drilled Examined Drilled Examined Drilled
Ash, green (Fraxinus pennsylvanica) 51 2.0 ete ba0 56 5.4 Bottomland woods
white (F. americana) 44 0 57 10.5 60 0 Upland woods, urban })
Beech, American (Fagus grandifolia) 4 0 121 3.3 Upland woods, urban "
(central) ;
Birch, paper (Betula papyrifera) 39 89.7 2 100.0 Urban q
river (B. nigra) OOD a00 75 0 Bottomland woods
Boxelder (Acer negundo) 82 1.2 8 0 69 8.7 Bottomland woods
Butternut (Juglans cinerea) 1] 27.3 oe9 5 60.0 Upland woods
Catalpa (Catalpa bignonioides) 1 0 13 15.4 1 0 Urban
Cedar, Chinese (Juniperus chinensis) ame 460 25 60.0 3 0 Urban
red (J. virginiana) 93 73.1 o 38 31.6 Upland woods
Cherry, black (Prunus serotina) 63 4.8 48 14.6 15 0 Bottomland & upland i
woods, urban
Coffee tree, Kentucky (Gymocladus dioicus) 3 0 4 0 12 0 Bottomland woods
Cottonwood (Populus deltoides) 56 3.6 62 4.8 61 0 Bottomland woods
Cypress, bald (Taxodium distichum) 6 0 5 20.0 59 6.7 Urban, bottomland
woods (south)
Elm, American (Ulmus americana) 36 28.1 37 37.8 136 6.6 Bottomland woods
Siberian (U. pumila) 3 33.3 11 9.1 0 Urban
slippery (U. rubra) 69 5.8 17 35.3 8 25.0 Bottomland woods :
winged (U. alata) cele a0 doe 20 0 Upland woods f
Ginko (Ginko biloba) 11 72.7 o90 Cs Urban
Gum, black (Nyssa aquatica) 40 38 5.2 Bottomland woods
sour (N. sylvatica) 3 33.3 38 0 Upland woods, urban ,
(central) ‘e
sweet (Liquidambar styraciflua) 32 84.4 115 2.6 Bottomland woods, q
urban (central)
Hackberry (Celtis occidentalis) 37 0 43 0 59 1.7 Bottomland, urban
Hawthorn (Crataegus sp.) eet 5.00 9 33.3 6 0 Bottomland, urban t
Hickory, bitternut (Carya cordiformis) 13 61.5 2 50.0 25 12.0 Bottomland woods, &
slopes i
kingnut (C. laciniosa) 62 17.7 Bottomland woods
mockernut (C. tomentosa) 6 66.7 75 25.3 Slopes, upland woods |
pignut (C. glabra) o0 <n 18 44.4 56 10.7 Upland woods i
shagbark (C. ovata) 68 54.4 104 53.8 127 23.6 Slopes, bottomland
woods i
sweet pignut (C. ovalis) doe one on 11 0 Slopes, upland woods z
Ironwood (Ostyra virginiana) 39 20.5 19 57.9 15 0 Upland woods, slopes }|_
Larch, European (Larix decidua) aoe 506 31 3.2 Urban re
Linden, American (Tilia americana) 84 23.8 62 79.0 3 33.3 Slopes, upland woods, re
ur ie
Locust, black (Robinia pseudoacacia) oe me 25 0 ul 0 Uplate i
honey (Gleditsia sp.) 3 0 48 0 26 4.2 Urban, bottomland
woods ;
Magnolia (Magnolia grandiflora) Bae 29 75.9 Urban f
Maple, Norway (Acer platinoides) ee oe 24 8.3 oC Urban 4
silver (A. saccharinum) 132 3.0 149 16.1 240 27.5 Bottomland woods
sugar (A. saccharum) 100 53.0 60 88.3 158 25.9 Woodland slopes
Mulberry (Morus sp.) cs 15 0 28 0 1 0 Bottomland woods
Musclewood (Carpinus caroliniana) 3 . 60 8.3 Bottomland woods and ‘

slopes

48

rilling incidence of only 1.5 percent. A rather un-
ommon tree, the butternut, showed a high incidence
50 percent of 5 trees). Many southern forest trees,
g., ashes, sweet gum, hackberry, and sycamore, which
vere fairly abundant were little used by sapsuckers.

Which trees are drilled may depend upon the sugar
ontent of the sap (Kilham 1964), but the species of
rees preferred by sapsuckers may be determined by
nore than the sugar content of the sap. Other chem-
cal constituents (e.g., tannins in oaks, Havera et al.
976) may influence the birds’ preferences. It seems
rovidential for the sapsucker that sucrose and rafh-
lose sugars in tree saps increase greatly in late winter
nd early spring (Anderssen 1929; Zimmermann &
filburn 1975), a time when other food sources may
ye scarce. The increase of sap and its nutrient con-
ent at an injury site (Kilham 1964) also benefits the
rd and may have been instrumental in the evolu-
ion of the habit of sap sucking.

In east-central Illinois woods the favorite trees for
apsuckers, based on drilling frequencies, were sugar

Taste 14.—Continued.

maples, lindens, pignut and shagbark hickories, and
ironwood. Williams (1975) found that sapsuckers in
his study area in east-central Illinois spent more time
on hickories than on any other trees. In an urban sit-
uation (Urbana, Ilinois) the trees most often drilled
by sapsuckers were paper birch, Austrian and Scotch
pine, tulip tree, linden, sweet gum, ginko, and Chi-
nese cedar. In northern Illinois (La Salle, Ogle, and
Winnebago counties) the trees most often drilled were
red cedar, shagbark hickory, sugar maple, and Scotch
pine.

Considering that winter sapsuckers are primarily
bottomland forest birds, the trees in upland woods
showed a surprisingly high incidence of sapsucker
drilling (Table 14). Migrant sapsuckers may be just
as plentiful in upland as in bottomland forest. The
total amount of forest in an area may help to deter-
mine which trees sapsuckers will drill, the birds using
upland forest or urban trees to a greater extent when
there is little native bottomland forest in an area.

Some tree species showed a gradation in the inci-

North East-Central South
Species Number Percent Number Percent Number Percent Site
Examined Drilled Examined Drilled Examined Drilled

Jak, black (Quercus velutina) 92 0 30 0 81 0 Slopes
bur (Q. macrocarpa) 19 26.3 67 28.4 4 0 Bottomland woods
cherrybark (Q. falcata pagodaefolia) Fae sie 506 500 34 0 Bottomland woods
overcup (Q. lyrata) ie 28 42.8 Bottomland woods
pin (Q. palustris) 42 23.8 70 1.4 Bottomland woods
post (Q. stellata) 506 208 506 S66 99 3.0 Upland woods
red (Q. rubra) 37 0 103 19 105 0 Slopes
shingle (Q. imbricaria) 300 ee 9 0 8 0 Upland edges of woods
Shumard’s (Q. shumardit) Sac wars 3 0 38 2.6 Bottomland woods
white (Q. alba) 101 1.0 80 10.0 200 1.0 Upland woods
yellow chestnut (Q. muhlenbergii) or =Se 416 21 9.5 Slopes

live, Russian (Eleagnus angustifolia) 12 100.0 tee Urban

’ecan (Carya illinoiensis) 61 31.1 Bottomland woods

ersimmon (Diospyros virginiana) 8 0 21 0 Upland, urban

(central)

‘ine, Austrian (Pinus nigra) 49 98.0 ond Urban .
loblolly (P. taeda) ae ai doe 138 21.0 Forest plantations —
Scotch (P. sylvestris) 38 97.4 62 87.1 ArG Forest edge plantation
short-leaf (P. echinata) 300 Sos 86 23.3 Upland woods :

\ slash (P. caribaea) ee 500 82 32.9 Forest edge plantation
western yellow (P. ponderosa) 20 0 vee Se Forest edge plantation

_ white (P. strobus) 167 25.1 35 8.6 15 20.0 Upland woods (north) 5

| urban & plantation
edbud (Cercis canadensis) 3 0 30 0 3 0 Upland woods, urban

assafras (Sassafras albidum) ess ee 8 0 22 0 Upland woods

yeamore (Platanus occidentalis) 18 27.3 63 20.1 97 1.0 Bottomland woods,
urban (central)

pruce, Norway (Picea abies) 77 9.1 36 19.4 Forest plantation,

| urban

hgarberry (Celtis laevigata) (a6 God 34 0 Bottomland woods

umac, staghorn (Rhus typhina) 10 0 Urban
ree-of-heaven (Ailanthus altissima) 28 0 tee ano Urban

ljulip tree (Liriodendron tulipifera) 39 74.4 51 37.3 Upland woods, urban

(central)
Jalnut (Juglans nigra) 23 21.7 43 18.6 44 11.4 Upland woods, urban
pillow, black (Salix nigra) 58 6.9 6 50.0 6 0 Bottomland woods
2 Tree species of which fewer than 10 occurred in our sample for the state have been omitted from this table.
49

dence of sapsucker use from the northern part of the
state to the southern part, e.g., the silver maple (Ta-
ble 14). It would be interesting to know if there is a
gradient in the sugar content of the sap from north to
south in the silver maple. We noted that different
tree species were drilled in different parts of the tree
and that different species were apparently attacked at
different ages. Sugar and silver maples were often
drilled at the base of the trunk when the tree was
fairly large (old). On the other hand, shagbark hick-
ories were often drilled at the 10- to 15-foot level
while the tree was fairly young. Inspection from the
ground level may give an erroneous impression of
the incidence of use by sapsuckers of a certain tree
species. For instance, the bur oak appears to be at-
tacked while fairly young. Later growth and the in-
crease in heavy corky bark tends to obscure old drill
holes. Cottonwoods appear to be drilled fairly high
in the tree while the tree is fairly young; thus, exam-
inations of old cottonwoods may not allow a ready
view of sapsucker holes from the ground level.

The locations of trees appear to influence the in-
cidence of sapsucker attacks also. The presence of a
more desirable (to the sapsucker) species may reduce
the use of a less desirable tree species in the immedi-
ate vicinity. Thus, in a grove of Scotch and Austrian
pines, about 10 percent of the Scotch pines were used
though the Austrian pines were all heavily drilled. In
another location, which had only Scotch pines, 85 per-
cent of them were drilled by sapsuckers. In some loca-
tions only less preferred trees occur, and in these
places such trees may be used of necessity, which
might account for the frequent drilling in parks and
urban plantings of sweet gum and sycamore, species
relatively little used in the native woodlands that we
examined. We also wonder if certain introduced tree
species are more vulnerable to sapsuckers because no
sapsuckers occur in the original ranges of these trees,
and hence, no defense mechanism has been evolved
by them. This lack of defense might explain the high
incidence of sapsucker attacks on certain introduced
pines (e.g., Austrian and Scotch pines) as compared
with native pines (e.g., white pine and short-leaf pine).
In New Hampshire Kilham (1964) found that sap-
suckers were more likely to attack trees which had
previously been injured.

In addition to the woody plants listed in Table 14,
we also found sapsucker holes in these species: com-
mon apple (Malus pumila) , arbor-vitae (Thuja occi-
dentalis) , horse chestnut (Aesculus hippocastanum) ,
Zumi crabapple (Malus zumi), grape (Vitis sp.),
American holly (Ilex opaca), magnolia (Magnolia
soulangeana), black maple (Acer nigrum), osage
orange (Maclura pomifera), paw paw (Asimina tri-
loba) , jack pine (Pinus banksiana) , red pine (P. res-
inosa), poison ivy (Rhus radicans), white poplar
(Populus alba) , rowan (Sorbus aucuparia) , and weep-

50

ing willow (Salix babylonica). These species were not
listed in Table 14 because of sample size (fewer than
10 trees observed). McAtee (1911), Gault (unpub-
lished notes 1891-1921) , and Wright (1926) observed
sapsucker damage on these additional species in Illi-
nois: red maple (Acer rubrum), flowering dogwood
(Cornus florida), magnolia (Magnolia tripetala),
shadbush (Amelanchier sp.), garden plum (Prunus
domestica) , and lilac (Syringa sp.) .

The present list obviously does not quantitatively
reflect Illinois tree populations. The list is far from
complete and does not include large portions of Illi-
nois, but more important than a complete list are
quantitative data on the relationship between sap-
sucker populations and tree populations. Swink (1965)
found the trees most frequently attacked by sap-
suckers at Morton Arboretum, Lisle, were “pines,”
“spruce,” tulip tree, sugar maple, basswood, and cot-
tonwood. He pointed out that sapsuckers showed a
preference for the tops of cottonwoods, which is where
we also often see them working near the ends of the
higher vertical branches. Swink’s (1959) study of
perching sites of sapsuckers, mainly in April in north-
eastern Illinois, showed the most frequently used trees
to be American elm, cottonwood, sugar maple, linden,
white oak, black locust, slippery elm, and white ash.

Sapsuckers can be very destructive to trees, disfig-
uring or even killing them. It usually takes several
years of sapsucker attacks to kill a tree, and even then
the direct cause of death may be some other agent,
such as fungus or bacteria that invade the sapsucker
wounds. We have found no reference to economic
damage to forests by sapsuckers in Illinois, where the
sapsucker winter populations are relatively low, but
the problem has been serious in areas further south
(McAtee 1911). Sapsuckers have, at times, been a lo-
cal problem in southern Illinois orchards, but the ex-
tent of the problem has never been measured quanti-
tatively. Complaints about sapsucker damage to yard
plantings seem to be increasing in Illinois, both in our
experience and that of Eugene Himelick, plant pa-
thologist, Illinois Natural History Survey. To some
extent, this increase probably reflects the greatly in-
creased human population in urban areas and the ac-
companying cost of, and pride in, landscape plantings.

HAIRY WOODPECKER
(Dendrocopos villosus)
(Fig. 38 and 39)

Spring Populations

There is no evidence of migration in Illinois pop-
ulations of the hairy woodpecker. Our counts of this
species are consistently low, and the spring counts
(Fig. 40) show less day-to-day variation through the

season than those for any other woodpecker except
the pileated, also a non-migratory species.

Distribution

The hairy woodpecker has a very wide distribution
in North and Central America (Fig. 39). In Illinois
the species is probably to be found the year around in

nearly every township though published records are
still lacking for large areas of the state (Fig. 41).

Nesting Habitats and Populations

The hairy woodpecker is essentially a forest spe-
cies in summer with very low populations, or none at
all, in other habitats. The species occupies both up-

Fig. 38.—Hairy woodpecker. The strong bill and immaculate outer tail feathers are characteristic of the species (compare with

downy woodpecker, Fig. 44) .

51

land and lowland forest, apparently favoring bottom-
land woods at least in central and southern Illinois.
Gates (1911) called the hairy a dominant species of
both bottomland woods and the more mesic upland
forest. In our censuses of southern Illinois forests, we
found more hairies, on average, in bottomland woods
than upland (Table 15). The highest populations
(10-24 birds per 100 acres) have been recorded in vir-
gin or mature bottomland forest in central Illinois
(Table 15). There are no measurements of hairy pop-
ulations in bottomland woods for northern Illinois,
but Schafer’s 1914-1923 unpublished censuses of up-
land forest in Rock Island showed high populations
for that habitat compared to those in the central and
southern regions (Table 15). Our strip censuses in
1957 and 1958 in the north, of 177 acres (about 16
miles) of forest (nearly all upland), did not intercept
a single hairy! The observation implies a population
decline since Schafer’s studies.

In northeastern Illinois Swink (1959 and 1965)
noted that hairy woodpeckers showed a definite pref-
erence for oaks, especially white oak forest.

Considering the relative abundance of its smaller
counterpart—the downy—the hairy woodpecker is sur-
prisingly uncommon in Illinois, and the available
data indicate that it always has been (Ridgway 1881a;
Nelson 1876-1877; Du Bois 1918; Cahn & Hyde 1929) .
On the Illinois River Barnes (1890) found the hairy
to be fairly common, but later (Barnes 1912) ob-
served that the species had become rare. He placed
the blame for the change on the house sparrow, which,
he said, appropriated almost every hairy woodpecker
nest in the area and even killed nestlings of the wood-
pecker (Bent 1939 ascribed this observation to Benja-
min Gault). In general, the population measurements
for the hairy suggest a continuing decline. Both
Barnes (1890) and Ridgway (1887) refer to the nest-
ing of hairy woodpeckers in orchards, a habitat not
now used at any significant population level. Even in
earlier times, however, hairy woodpeckers were rare in
man-dominated habitats, including residential habitat
(Ridgway 1887). The only other reference to inter-
specific aggression is that of Stickel (1963), who de-
scribed the conflict between a nesting pair of hairy
woodpeckers and red-bellies nesting in the same tree.

Hairy woodpecker habitat has not been analyzed
precisely. Silloway (unpublished manuscripts 1922
and 1923) repeatedly refers to hairy woodpeckers as
being in “large trees” or on “big tree trunks” in con-
trast to the downy woodpecker. There were no corre-
lations between summer numbers of hairy woodpeck-
ers and any feature or characteristic of the southern
Illinois woodlands examined by us in detail (see in-
troduction to this paper). Nor was there any appar-
ent relationship between this woodpecker and other
woodpecker species. Such relationships are hard to
discern in a species with such low population levels as
the hairy woodpecker has at present. The greatest
number of hairies in any of these southern woodlands

52

BREEDING

+ 1O*
: i
cin Hee toe te spo (
mae ; (
Oept of Geography ~ Univ. of Iilinois [ioe too" 20" Co [rot

Fig. 39.—General distribution of the hairy woodpecker. The
range shown here may include large sections in which popula-
tions of the species are thin or even absent because of the nature
of the terrain and lack of suitable habitat.

was 5.4 birds per 100 acres in one woodland in 1974
and 5.2 birds per 100 acres in another in 1975. There
were over three times as many hairies per acre in the
eight bottomland woods as in the five upland woods
studied (Table 15).

Hairy woodpecker territories measured in McLean
County by Calef (1953a) in mature bottomland forest
ranged from 1.6 to 3.7 acres, averaging 2.6 acres. Also
in central Illinois (Piatt County) Allison (1947) mea-
sured one territory—6.5 acres—in mature upland for-
est. This territory was more than twice the size of
downy woodpecker territories (average of four: 2.7
acres) in the same area.

There are site data for only 17 hairy woodpecker
nests, mainly in northern and central Illinois. About
one-third of the nests were in dead branches of living
ashes, elms, and birches; one-third in dead trees or
stumps; and one-third in living willows, elms, oaks,
and maples. Most of the nests were 15-35 feet high,
but one was as low as 5 feet (Hess 1904) .

Nesting Cycle

There are only fragmentary data on the nesting
cycle of the hairy woodpecker in Illinois. In Central
Illinois Fawver (1947a) observed hairy woodpeckers

establishing territories about the first week in April,

but some courtship behavior begins before then. In
northeastern Illinois Gault (unpublished notes 1906,

1907, and 1927) referred to what he called “mating”

or “courtship” behavior by hairies in aggregations of
four or more birds throughout March. Vocalizations
have not been studied in Illinois, but Lawrence (1967)
pointed out that the hairy’s courtship display involves
rather spectacular bounding flights.

Hess (1910) considered the hairy to be the earliest
nesting woodpecker in the Philo area. If cavity exca-
vation has been observed in Illinois, the observation
has not been published. Hairy woodpecker nest cav-
ities in Illinois have varied from 10 to 15 inches in
depth, with entrance holes ranging from 114 to 214
inches in diameter (Loucks unpublished notes 1893;
Fawver 1947a; Calef 1953a). One cavity was 414
inches wide (Chicago Museum of Natural History
oology specimen label 16552). Link (1945) stated
that the cavity entrance for the hairy woodpecker was
134 inches in diameter, and Ford (1939) gave these
specifications for a cylindrical nest box for the hairy:

Weg 12. 24

floor, 6 inches in diameter; depth, 12-15 inches; en-
trance above floor, 9-12 inches; and diameter of en-
trance, 114 inches, the box to be placed 12-20 feet
high. We know of no case of the use of a nest box by
the hairy in Illinois.

Like the rest of the cycle, the egg-laying season of
the hairy woodpecker is poorly known in Illinois. The
eggs are the typical immaculate glossy white of wood-
peckers. In central Illinois Hess (1904) referred to a
nest with four eggs on 24 April, and there is a Chi-
cago record of a nest with two eggs on 30 April (Anon-
ymous 1877). Most of the ‘‘fresh-egg” sets in museum
collections and those referred to in the literature were
laid in May, especially 1-20 May. However, there are
references that indicate much earlier laying. Sanborn
(1922a) found two nests on the Kankakee River in the
period 20-22 May, with young ready to fledge, and
R. M. Barnes (Chicago Museum of Natural History
oology specimen label 7340) referred to a nest at La-
con with three addled eggs and one young ready to
fledge on 8 May. If we assume an incubation period
of 11-12 days and a nestling period of 28-30 days

NORTH

yess LAYING (SPAN OF DATES) O

Q © O

= FEB OMAR = OAPR) «MAY = JUN JUL. AUGSSEP_ OCT
=)
5 ee CENTRAL
a
=
Y
=
= FER =«OMAR «Ss APR'-—«Ss‘“‘<‘AYS=«=Ss«SUN = JULSSssAUGSs«SEP'—Ss«OOCTT
Oo
2 af SOUTH i
(Oo) O OO O OO O

Oy A A Of XO O00 O
000 O

| eee eee ee I? 24 1224 2 24 2 28 12 24
| FEB MAR APR MAY JUN JUL AUG OCT

Fig. 40.—Numbers of hairy woodpeckers seen throughout the spring and fall seasons, with the span of egg-laying dates shown
by the stippled area. The graph line represents higher count of each 4 days of a continuous record (1967-1970). Hollow circles
represent counts from other years or other observers.

12 24
SEP

| 53

NESTS OR YOUNG

@ 1950 —
A 1900-1949

@ BEFORE 1900

JUNE RECORDS

O 1950 —

A 1900 — 1949

OO BEFORE 1900

Fig. 41.—

HAIRY WOODPECKER
BREEDING RECORDS

ieee Oe

ruton J me Cean =
| y, | e ea za ae ¢
P. 4 )
uason | Srl r :
| ot wit, i VERMILION
regan | (7 glee
cass) “ORL | A |
oS yes Ale lap
\ woncan | Myencamon > T a1 pow
io al = Sy pee tocar |
4 cHmistan Tet Vecoues
7 ye poet
rte EOL) al reg CLARK
Te } 'UMBERLAND|
Sper uscousle | wonrcoweny | | F al
i} LC ¥
pt tt yee orm JASPER
L pono +t+10
) Maoison aoe ll es
o— o2\5 — fy
anion N
cunt pees)
sre pasa
Rae Amps WAR
Osxecron
vomot f UEFFERSON

<a Perey

BAe

4 «
=

a KLIN |
im

a pe “= ox rn
Ome 5... ay o

Mo ian vate

Distribution of breeding records of the hairy wood-

pecker in Illinois. Hollow symbols represent birds seen or heard

in June.

TasBLe 15.—Breeding populations of hairy woodpeckers in Illinois.

(Lawrence 1967), eggs in the Kankakee nest couk
have been laid as early as 9 April, and those in th.
Lacon nest might have been laid even in late Marchi
depending upon how near the young were to fledging:
There are no egg-laying dates for southern Illinois.

We have found clutch data on only 13 Illinoi
nests with eggs, none in the south. The distributioi|
of clutches was: six eggs, two nests; four eggs, eigh:
nests; and three eggs, three nests. The absence of five
egg sets is probably only an accident of the small sam’
ple. Hess (1904) pointed out that the incubating
adult sits very close and is difficult to dislodge fron)
the eggs.

Most nests have been found with young fairly wel
grown, as the young are often noisy then and con
spicuous.

There are no data on nesting success or produc
tivity.

Fall Populations

The events of late summer and fall among the
hairy woodpecker populations of Illinois are partic
ularly obscure. Though no migration is known, ther
is some movement by at least part of the populatior
to nonforest habitats, including most notably urban’
residential areas. We first noted a hairy in open coun
try on 13 September in the south.

We have seen hairy woodpeckers in what appearec’
to be fresh plumage as early as 4 September, anc
others obviously in heavy molt on 11 September
George (1972) observed that it took about 4 month
for juvenile hairies to complete the molt and pointea
out that some juveniles may still be aged on the basis’
of their primaries well into October.

® All figures were converted to birds per 100 acres (territorial males or nests « 2

|

a ‘ :

* Birds per Type of Region or

Habitat Acres 199 Acres® Years Genene County Reference

Oak-maple forest 55 0-7 1927-1975 Map Champaign (C) ” Kendeigh 1944

(avg 3.2) |

Oak-maple forest 64 9 1943, Map Champaign (C) Johnston 1947

Forest (all types, including edge) 214 1-4 1957-1958 Strip Central Graber & Graber 1963,

(avg 2.8) ;

Forest (all types, including edge) 340 2-4 1957-1958 Strip South Graber & Graber 1963 |

(avg 2.6)

Forest (unspecified) 20 10 1914-1916 Nest Rock Island (N) John J. Schafer (unpub- |

lished notes 1914-1923) ©

Forest (unspecified) 54 49 1917-1923 Nest Rock Island (N) John J. Schafer (unpub- H

(avg 7.1) lished notes 1914-1928) © i

Mature upland forest 479 0-1 1974-1975 Strip South This paper

(avg 0.4) :

Mature bottomland forest 1,077 0-5 1973-1975 Strip South This paper i
(avg 1.3)

Virgin floodplain forest 77 10 1948 Map Sangamon (C) Snyder et al. 1948

Virgin floodplain forest 50 4 1947 Map Piatt (C) Fawver 19476

Mature bottomland forest 63 17-24 1950-1951 Map McLean (C) Calef 1953a

(avg 20.6) |

Upland second-growth oak- 56 4 1941-1942 Map Sangamon (C) Robertson 1941b, 19420

hickory forest |

Upland oak-hickory forest 24 4 1967 Map Hancock (C) Franks & Martin 1967 |

> C refers to the central region of Illinois and N to the northern, as shown on winter distribution maps, e.g., Fig. 5.

54

Our daily counts of hairy woodpeckers in the state
were higher in fall (August—October, inclusive) than
in spring (March—May, inclusive) but only slightly:
1.3 in fall to 1.0 in spring. The ratio was higher in
both the north (2.1:1.0) and south (1.5:1.0), but in
central Illinois the ratio (1.0 to 1.2) showed a slight
decline in fall. The data seem to indicate poor pro-
ductivity. Banders should make an effort to get age
ratios on this species in fall, using the primary char-
acter (George 1972).

Winter Populations

The hairy woodpecker is to be expected in every

county in winter, and the absence of records for a
number of counties is probably only indicative of a
shortage of study in those areas (Fig. 42). Hairies are
regularly detected on virtually all Christmas counts.
Several observers, particularly in northern Illinois,
have noted that hairies are conspicuously more com-
mon in winter than in summer (Nelson 1876-1877;
Eaton 1878; Smith & Beecher 1958). At least a few
hairy woodpeckers move to more open habitats in
winter, but this is not a major population shift (Ta-
ble 16). In the south, however, there is a notable
shift by hairies to greater use of urban residential hab-
itat and upland forest in winter. In our 1974-1976
censuses in the south, winter population density, on
he average, declined slightly from summer levels in
es but increased in upland forest.
_ The winter population densities from the cross-
country censuses of 1907 and 1957-1958 indicate a de-
cline of the hairy, at least in southern Illinois, where
the largest samples were taken (Table 16). The
Christmas counts also show a downward trend since
1900 (Fig. 43). As there were few counts in the south
‘n the early years, the data for that region are the
‘east dependable. On the other hand, the northern
ind central counts show the same pattern, and their
p-year averages (Fig. 43) are significantly correlated
(r = 0.924, P= < 0.001).

Cooke (18856) called the hairy woodpecker abun-
dant in Union County and reported seeing 10-20 per
jay. Our highest count during the forest censuses
(two observers in one party) was six hairies in 4 hours
—also in Union County.

The numbers of hairy woodpeckers in winter show
positive correlations with the numbers of large trees
per acre (trees over 22 inches DBH) both in upland
ind bottomland habitats (r = 0.987 and 0.910, respec-
ively, P = < 0.001). They also show positive corre-
ations with the diversity of genera and species of
arge trees. For upland woods the correlation be-
tomb the number of genera of large trees and the

umber of hairy woodpeckers is 0.953 (P = < 0.01)
ind for the species it is 0.996 (P = < 0.001). For
pottomland woods the correlation was 0.828 for num-
per of genera of large trees and 0.822 for number
PE species (P = < 0.01). In other words, in winter

this woodpecker seems to prefer mature woods with a
variety of large trees present.

There may be some competition or conflict be-
tween hairy woodpeckers and red-headed woodpeckers.
There is a negative correlation between the num-
bers of these two species (r = —0.772, P= < 0.02) in
bottomland woods. Conversely, the numbers of hairy
and red-bellied woodpeckers showed a positive cor-
relation in six of the eight bottomland woods ex-
amined (r = 0.768, P = <0.05).

Food Habits

‘There are numerous references to hairy woodpeck-
ers at feeders, especially at suet (Childs 1922; Lampert
1922; Patterson 1923; Cone 1956). At a feeder in Ot-
tawa, Bellrose (1954-1935) observed the hairy to be
shyer than the downy but dominant over the smaller
species in conflicts. At Glen Ellyn, Gault (unpublished
notes 1894 and 1914) observed a hairy feeding on pot-
son ivy fruit in October. In Union County in winter

HAIRY WOODPECKER
WINTER RECORDS
DEC. 15 - FEB.1

: wg nis.
By aemlasoiiel
ew PB lAlae

@ 1950- "y
—s)

many Go | as
Fea eo
eal ica,

A 1900- 1949

M BEFORE 1900

Fig. 42.—Distribution of winter records of the hairy wood-
pecker in Illinois. The three regions of the state referred to in
the text are separated by the two heavy horizontal lines.

55

TABLE 16.—Winter populations of hairy woodpeckers in Illinois.

Habitat

Urban residential
Urban residential

Suburban woodlot
Oak-maple forest

Oak-maple forest
Forest
Forest
Forest

Forest
Forest

(all types, including edge)

(all types, including edge)
(all types, including edge)
(all types, including edge)
(all types, including edge)

Forest (all types, including edge)
Forest (all types, including edge)

Mature upland forest
Mature bottomland forest
Bottomland forest

Grazed bottomland woods

Shrubby field and forest edge

Shrubby field and forest edge

70-85

40

Birds per Years Type of Region or
100 Ane (January) Census County Referees
0 1976 Strip North & Central This paper
14 1976 Strip South This paper
(avg 2.1)
10 1968-1972 Map Lake (N)? Miller & Miller 1972
0-4 1925-1948 Map Champaign (C) Kendeigh 1944, 19484
(avg 2.5)
2-7 1949-1975 Map Champaign (C) Kendeigh et al. 1957;
(avg 3.2) Kendeigh 1973
0-2 1940-1941 Map Piatt (C) Johnston 1942
(avg 1.1)
3 1907 Strip North Graber & Graber 1963
0 1957-1958 Strip North Graber & Graber 1963
2 1907 Strip Central Graber & Graber 1963
3-6 1957-1958 Strip Central Graber & Graber 1963
(avg 4.6)
3 1907 Strip South Graber & Graber 1963
0-2 1957-1958 Strip South Graber & Graber 1963
(avg 0.9)
0-3 1974-1976 Strip South This paper
(avg 0.9)
0-5 1974-1976 Strip South This paper
(avg 0.9)
2-6 1950-1953 Map Cook (N) Montague 1950, 1953
(avg 3.0)
24 1955-1957 Map Macon (C) Chaniot & Kirby 1955b,
(avg 2.5) 1956; Kirby & Chaniot
1957
(+)” 1948, 1955— Map Richland (S) Hundley et al. 1956
1956
0-2 1960-1965, Map Lawrence (S) Shaw 1961;
1968 Axelson et al. 1965

aN refers to the northern region of Illinois, C to the central region, and S to the southern, as shown on winter distribution maps, e.g., Fig. 5.

> The plus symbol (+) indicates fewer than one bird per 100 acres.

Cooke (1885b) noted that hairy woodpeckers dam-
aged corn in fields adjacent to forest, but Beal’s (1911)
extensive study of stomach specimens from 33 states
showed that corn was an insignificant part of the
hairy’s diet. His study showed the hairy to have one
of the most consistent diets through the year, being

2.0
|

\ CENTRAL

BIRDS PER PARTY HOUR

05 15 25 35 45
1900 1910 1920 1930 1940 1960 1970
Fig. 43.—Hairy woodpeckers seen per party hour on Audubon
Christmas counts in the three regions of the state. Each point
represents a 5-year average.

1950

56

75

about 78 percent animal matter and 22 percent vege-
table. In June the animal content went as high as-
90 percent.

The dominant foods, constituting about 31 percent»
through the year and reaching as high as 41 percent in ©
December, were the larvae of wood boring beetles, es- '
pecially Cerambycidae, Buprestidae, and Lucanidae. ‘
Some stomachs had large numbers (up to 100) of:
such larvae. Beal (1911) found ants to be the second »
most important item in the hairy’s diet, constituting |
about 17 percent (27 percent in January) and, like»
the borers, present every month. Caterpillars, the
third most important food, were also present every
month and made up about 10 percent of the food. —
Webster (1881) and Waldbauer et al. (1970) pointed ©
out the importance of hairy and downy woodpeckers |
as predators on cecropia cocoons.

Of the vegetable food, Beal (1911) found that
about 5 percent of the diet was fruit, mainly wild —
(sassafras, dogwood, sumac, etc.). About 11 percent |
was mast, notably beechnuts, hazelnuts, and acorns.
Seeds, such as foxtail, vervain, and mustard made up
about 4 percent of the diet.

Longevity

Hairy woodpeckers appear to be rather long-lived.
Reuss (1963) reported on a hairy woodpecker that

vas banded in Cook County, 9 November 1952, and
eturned on 3 November 1963, making it at least 11]
ears old—the oldest on record in Illinois. Two other
airy woodpeckers (males) banded in northeastern
llinois were at least 7 and 8 years old, respectively
computer printout from U. S. Fish and Wildlife Ser-
ice Bird Banding Office 1972 and 1974). Bartel’s
1964 and 1967) oldest banded hairies were just under
years. There are no studies of age distribution for
ny Illinois population of hairy woodpeckers.

There is but one reference on any mortality factor
f the hairy. Brown & Bellrose (1943) found hairy
yoodpeckers to be 3 of 259 identified prey items of
creech owls in southern and central Illinois, probably
nainly in winter. Only seven of the prey items were
lownies—i.e., about twice the number of hairies. Our
inter counts indicate a ratio of about six dowines to
ne hairy in the south, which is also the ratio of the
wo species in the Christmas counts. The ratio shown
n central Illinois Christmas counts was about five
ownies to one hairy. These observations imply that
creech owls are more likely to catch hairies than
ownies.

pecimen Data

There are several references to the occurrence of
wo races of hairy woodpeckers in Illinois (Ferry
907b; Howell 1910; Ridgway 1914; and others).
erry (19076) pointed out that specimens from south-
rn Illinois were small, resembling in that respect the
rm D. villosus audubonii of the southeastern USA.
n color, however, the southern Illinois specimens
rere clear white below, as in D. v. villosus. All Illi-
ois specimens we have seen have been thus colored
nd are probably best referred to the nominate race.

There is a suggestion of size difference between
airies from north of the latitude of Pike County and
lose from south of Pike County, but presently there
re too few specimens available to determine whether
1e change is consistent and whether it is merely a
nooth cline with latitude.

The wing and tail length ranges and means for
x northern and central males (worn, molting, and
ienile specimens excluded) were: wing, 118-124
1m (mean: 120.1 mm, sp: 2.23); tail, 74-78 mm
nean: 76.5 mm, sp: 1.16); and for five southern
lales: wing, 112-118 mm (mean: 115.4 mm, sp:
46); tail, 59-71 mm (mean: 67.5 mm, sp: 4.81).
feasurements for three northern and central females
ere: wing, 116-124 mm (mean: 119.3); tail, 70-77
1m (mean: 73.2 mm); and for eight southern fe-
lales: wing, 110-118 mm (mean: 113.6 mm, sD:
44) ; tail, 63-71 mm (mean: 67.9 mm, sp: 2.75).

We have but four weight records for Illinois hairy
oodpecker specimens, one male and three females.
Veights of the females, all taken in January—February
1 southern Illinois, were 58.0, 60.5, and 66.0 grams.
_male from Union County weighed 68.5 grams in
=>ptember.

DOWNY WOODPECKER

(Dendrocopos pubescens)
(Fig. 44 and 45)

Spring Populations

There is no proof that downy woodpeckers migrate
in Illinois, despite some suggestions to the contrary
(Woodruff 1907; Anonymous 1916; Swink 1959; Gra-
ber & Graber 1963). Cooke's (1888) explanation of
the downy’s apparent population shifts as more or
less local winter wandering to forage is probably the
most reasonable. The published banding records for
downies in Illinois (Cooke 1937 and 1950; Bartel
1959a, 1959b, and 1964; Lincoln 1924 and 1927) in-
clude no record of a recovery very far distant from
the place of banding.

The presence of 10 downy woodpeckers among
humerous night migrants killed in Lake Michigan
during the disastrous storm on the night of 16 April
1960 (Segal 1960) is not necessarily indicative of mi-
gration, as the birds may have been blown from
perches along the lake shore.

Despite the absence of migration in this species,
the pattern of the daily counts of downy woodpeckers
(Fig. 46) has peaks in spring and fall similar to the
patterns for migratory species. These peaks probably
reflect activity related to changes in habitat and habit
from winter foraging to nesting and back, as noted
by Cooke (1888), Twomey (1945), and Graber &
Graber (1963). Twomey (1945) noted this change
about 1 May in east-central Illinois.

Distribution

Downy woodpeckers of one form or another oc-
cupy nearly all of North America where there are
trees (Fig. 45). In Illinois they are probably to be
found in every township though the published record
is still very incomplete (Fig. 47) .

Nesting Habitats and Populations

With the onset of nesting, downy woodpeckers
become primarily forest dwellers, particularly of the
forest interior (Kendeigh 1944; Twomey 1945). In
central Illinois Hess (1910) and Hankinson (1915)
noted that downies were more common in lowland
forest than in upland, and our data for southern
Illinois forests (Table 17) also show downy popula-
tions consistently higher in bottomland than in up-
land. The highest population densities for downies
have been recorded in virgin or old lowland forests
(Table 17). Shrub areas have population levels
similar to those in upland forests. “The woody hab-
itat with lowest populations of downies is urban
residential habitat (Table 17). Within the bottom-
land forests sudied by us in southern Illinois, there
was a positive correlation between summer numbers
of downies and the percentage of the total basal area

57

ress

EE

i

Fig. 44.-Male downy woodpecker. Note the small bill and the bars on the outer rectrices (compare with hairy woodpecke)

Fig. 38) .

of medium sized trees (10-22 inches DBH) (r=
0.867, P= < 0.01). We found a negative correlation
between downy numbers and the percentage of total
basal area contributed by large trees (r= — 0.834,
P=< 0.01). There was a positive correlation be-
tween downy populations and the numbers of dead
trees in the southern Illinois woodlands (r= 0.799,
P=< 0.01). This correlation agrees with observa-
tions in central Illinois by Williams (1975), who
noted extensive use of dead trees in bottomland woods
by downies, although downy woodpeckers did not

58

|

show the great increase in numbers apparent in th!
red-head population following a massive tree kill fron
flooding in Calhoun County (Yeager 1955).

In the upland woods studied by us in southeri
Illinois, we found no correlations between densit
(number per acre), basal area, and sizes or kinds o
woody plants present and downy numbers. Ther’
was a correlation between downies and red-bellies
woodpeckers (r = 0.804, P= ca 0.05), suggesting tha
these two bird species prefer similar habitat in thi
uplands. |

oro 400 400 00
ee J
mle om

Deol of Geography -Univ_ of itirove ho* 100% oot so >

Fig. 45 —General distribution of the downy woodpecker. The
range shown here may include large sections in which popula-
tions of the species are thin or even absent because of the nature
of the terrain and lack of suitable habitat.

In northeastern Illinois Swink (1959 and 1965)
found that downies were most often seen in white
oaks, bur oaks, elms, willows, and hawthorns. William
Starrett (personal communication) found downies
particularly common in stands of willow on the IIli-
nois River. The most commonly recorded nest trees
of downy woodpeckers have been willows and elms,
but the vast majority of nests are in dead trees or
dead branches of trees, and a variety of species have
been used, including willow, red oak, white oak, plum,
silver maple, apple, ash, crabapple, shagbark hickory,
sassafras, sycamore, and tree-of-heaven. The heights
of 41 nests ranged from 4 to 50 feet and averaged
19 feet.

Our observation that downy populations were
notably higher in central Illinois than in either the
north or south (Graber & Graber 1963) is puzzling,
as population densities within a given habitat do

ot ordinarily change so abruptly. The observation
eeds corroboration from studies on larger census
Les on forest tracts of comparable quality between
regions.

Breeding territories of downies in mature lowland

Q

forest measured in central Illinois by Calef (1955c)

and Fawver (1947b) ranged from 1.3 to at least 4.7
acres. Calef (1953a) measured nine downy territories
in 1950 (range: 1.3-3.1 acres, average: 2.0 acres) and
four in 1951 (range: 1.3-2.1 acres, average: 1.5 acres).

Nesting Cycle

Johnston (1944) has described the courtship be-
havior of the downy woodpecker in central Illinois.
At such times the birds are noisy, and their chasing
episodes often involve three or more birds together.
The increased conspicuousness from this behavior
probably accounts, to some extent, for the generally
high counts in spring (Fig. 46). Musselman (1937)
has noted “drumming” behavior by downies as early
as 5 January, but active courtship is not usually ob-
served in central Illinois until late February or March,
continuing at least through April. The periodicity
of neither calling nor drumming has been studied.
Jackson (1919) gave phonetics for the common call
note as “pique,” which, when repeated rapidly, makes
a kind of song (trill). Mating and nest excavation
have been observed most often in late April in central
and northern Illinois (Ford et al. 1934; Coursen 1947;
Fawver 1947a; Gault unpublished notes 1910), but
observations are lacking for the south. The use of
nest boxes by downies has never been recorded in
Illinois, and is apparently rare, but Ford (1939) rec-
ommends these house dimensions for the species:
floor, 4 x 4 inches; depth of cavity, 8-10 inches; en-
trance above floor, 6-8 inches; and diameter of en-
trance, 114 inches. Calef (1953a) measured natural
nest cavities of downies in Funks Grove and found
them to vary from 2.5 to 4 inches in diameter and
from 7 to 10 inches in depth, with entrance holes
1.1-1.5 inches in diameter. Link (1945) notes the
nest entrance to be 1.5 inches for downies. The time
requirement for cavity construction has not been re-
corded in Illinois, but Lawrence (1967) recorded the
time at eight nests as 13-20 days. No nest other
than the cavity is built.

The earliest egg laying by downies, known to us,
was 30 March in southern Illinois and more than a
month later in the north (Fig. 46). The duration of
the laying season is very poorly known but extends
to at least 1 June in the north (Fig. 46). The appar-
ent brevity of the laying season probably reflects more
the paucity of study than the actual biology of the
species. The eggs, typical of those of woodpeckers,
are immaculate white. Twenty-two sets of eggs,
mainly old (around 1900) museum specimens from
northern Illinois, showed this distribution of clutches:
six eggs, 5 (23 percent) ; five eggs, 14 (64 percent) ;
four eggs, 2; three eggs, 1. The incubation period has
not been measured in Illinois, but Lawrence (1967)
found the period to be 12 days in Ontario.

Young birds have been observed out of the nest
in central Illinois as early as 3 June (Fawver 1947a)

59

,
i

and in the north by 9 and 10 June (Ford et al. 1934; the duration of parental care extends at least 3 wee), |
Sanborn & Goelitz 1915). By mid-June groups of beyond fledging (Lawrence 1967) .

wandering young and adults are common in central Nesting success has never been measured for an
Illinois (Weise 1951). The length of nestling life, Illinois population of downies. Strangely (for a cavil\
20-22 days, is relatively short for a woodpecker, and nester) there is no reference in the Illinois literatua
(i

20 ‘

BIRDS COUNTED PER DAY

NORTH i

O

EGG LAYING q

10 SPAN OF DATES {

2

12 24" 12 24° 12 24° 12 24° 12 24° 12 24° 12 24 a 2!

FEB MAR APR MAY — JUN JUL AUG SEP OcT.

20 CENTRAL

10

12 26" 12:24° 12 24° 12 24° 12 26" 12 24° 12 24 12975

30 FEB MAR APR MAY JUN JUL AUG SEP OCT.
sal © L |
SOUTH

fe) fe)
10 EGG LAYING o O
SPAN OF DATES O 5 fe

12 24" 1224" 12 24° 12 24' 129 24’ 12 24! 12 24! 12 24
FEB MAR APR MAY JUN JUL AUG, = SEE OCT.

Fig. 46.—Egg-laying season (shaded area) and numbers of downy woodpeckers seen in spring, summer, and fall in the three Te

gions of Illinois. The graph line represents the higher count of each 4 days during spring and fall from a continuous daily recon
made in 1967 and 1970 in southern Illinois, in 1969 in central Illinois, and in 1968 in northern Illinois. Hollow circles show num)
bers seen in other years or by other observers. |

60

DOWNY WOODPECKER
BREEDING RECORDS

“STS OR YOUNG <

Sea
i eae SE A.

1950 —

1900 — 1949
BEFORE 1900
NE RECORDS
1950 —

1900 — 1949

BEFORE 1900

ale
"0 10 20 39 40 _SQnites
SS a

Fig. 47.—Distribution of breeding records of the downy
odpecker in Illinois. Hollow symbols represent birds seen
heard in June.

nest competition between downies and other spe-

2s though downies have been seen attacking wrens
hilds 1923) .

Il Populations

In late summer downy woodpeckers become quiet
id inconspicuous for a time, probably coincidental
th the molt. In northern Illinois we have seen
wnies about half through the molt in mid-August
id early September. George (1972) indicated that
€ molting period extends into October.

Hulsberg’s (1917-1918) statement that downies
re coming into town by | September is the only
servation on the timing of the post-breeding hab-
it changes of the species. Actually their dispersal
obably begins in July and August but may not be
parent in urban areas until later. This dispersal
ukes the birds more conspicuous, increasing the
ily counts (Fig. 46). Our highest counts of downies
me consistently in September, as did also those of
ink (1959) .

Our spring (March-May) and fall (August
tober) counts showed a statewide ratio of 1.0

downy woodpecker in spring to 1.9 in fall, the ratio
being highest in the north (1.0:2.1) and lowest in
the south (1.0:1.7).

Winter Populations

Downy woodpeckers probably occur in every town-
ship in the state in winter, but published records are
still lacking for a number of counties (Fig. 48). From
population densities we conclude that favorite winter
habitats are bottomland forest and shrub habitat, but
even corn stubble fields have a fairly consistent,
though thin, winter population of downies (Table
18). The downy population in urban areas increases
notably in winter over summer levels.

Bottomland woods are an important part of the
winter habitat of downy woodpeckers in southern IIli-
nois; over two times as many were found in bottom-
land as in upland woods. There was a correlation
between downy numbers and the Importance of
Ulmus (r= 0.613, P= < 0.10). There was a similar
degree of correlation for large-tree basal area. The
converse was also true—a negative correlation be-
tween downies and the basal area of small (r=
— 0.638, P= < 0.10) and medium-sized trees (r=
— 0.665, P= 0.05). These data indicate an ecological
difference between winter and summer downy habitat
within the same woodlands, since in summer the corre-
lations were reversed.

In uplands downies seem to choose woodlands
with ash trees present (r= 0.969, P= < 0.01) and
to avoid, or at least occur in lesser numbers in, woods
with oaks (r=— 0.851, P= < 0.05) or _hickories
(r= — 0.960, P= < 0.01). This indicates a_pref-
erence for a more mesic upland forest. There was
also a correlation (r= 0.985, P= < 0.001) between
downy numbers and upland forests with high per-
centages of the basal areas made up of large trees,
just as in the bottomlands. There were negative
correlations for high basal-area ratios of small and
medium-sized trees (r= —0.872, P=< 0.05; r=
— 0.979, P= < 0.001, respectively). There was a cor-
relation between downies and the number of large
trees (over 28 inches DBH) per acre in upland woods
(yr = 0.942, P= < 0.01). In upland woods there was
a positive correlation between the downy and the red-
bellied woodpecker (r=0.973, P= < 0.001). The
diet of these two birds indicates little or no competi-
tion between them for food in winter.

From the regional variation in downy woodpecker
winter populations, based on the statewide censuses
(Graber & Graber 1963), we concluded that there was
at least one migratory population of downies in the
state. There is still no proof based on the recovery
of banded birds that such a migration exists. For the
entire state the ratio of summer to winter downy
woodpecker numbers was 1.0 (summer) to 1.8 (win-
ter) , a slight decline from the fall ratio. Because the
fall ratios were roughly similar in all regions of the
state, we would expect, lacking migration, that the

61

TasLe 17.—Breeding populations of downy woodpeckers in Illinois.

Habitat Acres oe Years AEeS yest 3g Reference

Urban residential 160 1 1958 Strip North Graber & Graber 1963

Urban residential 173 0 1958 Strip Central & South Graber & Graber 1963

Unmodified woodland 27 7 1937 Nest Lake (N)° Beecher 1942

Oak-maple forest 55 4-22 1927-1943 Map Champaign (C) Kendeigh 1944
(avg 13.5)

Oak-maple forest and edge 55 4-48 1944-1975 Map Champaign (C) Kendeigh & Forsyth 1959;
(avg 16.7) Kendeigh & Barnett 1967

Oak-maple forest 64 16 1943 Map Champaign (C) Johnston 1947

Forest (all types, including edge) 177 2-5 1957-1958 Strip North Graber & Graber 1963
(avg 3.4)

Forest (all types, including edge) 214 11-13 1957-1958 Strip Central Graber & Graber 1963
(avg 12.1)

Forest (all types, including edge) 60 5-15 1907, 1909 Strip South Graber & Graber 1963
(avg 8.3)

Forest (all types, including edge) 340 3-4 1957-1958 Strip South Graber & Graber 1963
(avg 3.5)

Mature upland forest 479 1-8 1974-1975 Strip South This paper
(avg 3.1)

Mature bottomland forest 1,077 3-26 1973-1975 Strip South This paper
(avg 9.2)

Mature bottomland forest 63 16-30 1950-1951 Map McLean (C) Calef 19534
(avg 23.0)

Virgin floodplain forest 77 36 1948 Map Sangamon (C) Snyder et al. 1948

Virgin floodplain forest 50 20 1947 Map Piatt (C) Fawver 1947b

Grazed bottomland woods 53 19 1955 Map Macon (C) Chaniot & Kirby 19556

Woods, unspecified 20 10-20 1914-1916 Nest Rock Island (N) John J. Schafer (unpub-
(avg 16.7) lished notes 1914-1923)

Woods, unspecified 54 7-11 1917-1923 Nest Rock Island (N) John J. Schafer (unpub-
(avg 8.1) lished notes 1919-1923)

Second-growth hardwoods 15 13-27 1937-1938 Map Rock Island (N) Fawks 1937, 1938
(avg 19.9)

Upland second-growth 56 4-11 1941-1942, Map Sangamon (C) Robertson 19416, 19426,

oak-hickory forest (avg 7.1) 1944 1944b
Upland second-growth 46 13 1948 Map Sangamon (C) Robertson & Snyder 1948
oak-hickory forest

Upland oak-hickory 24 8 1967 Map Hancock (C) Franks & Martin 1967

Scrub oak-hickory 40 4 1968 Map Mason (C) Johnson 1970

Late shrub 21 18 1966 Map Vermilion (C) Karr 1968

Shrubby field and forest edge 60 2 1949 Map Richland (S) Stine 1949

Shrub areas 39 5 1909 Strip South Graber & Graber 1963

Shrub areas 129 2-3 1957-1958 Strip South Graber & Graber 1963
(avg 2.3)

Swamp and thicket 13 2 1950 Map Jackson (S) Brewer & Hardy 1950

Swampy prairie 64-67 3 1941-1942, Map Sangamon (C) Robertson 1941a, 1942a,

1944

1944a

a All figures were converted to birds per 100 acres (territorial males or nests X 2). ae 4 ‘i
DN refers to the northern region of Illinois, C to the central, and S to the southern region, as shown on winter distribution maps, e.g., Fig. 5.

winter ratios would also be similar in all regions.
However, data from the cross-country censuses indi-
cated that although the winter populations of downies
were far above the summer populations in northern
and southern Illinois, the population actually de-
clined in winter in central Illinois. A similar pattern
is shown in the population data for Trelease Woods
(Kendeigh and others 1941-1975) where the long-term
average for the downy population is lower in winter
than in summer. The resolution of this paradox
would seem to require a large-scale banding of
downies, especially in central Illinois.

In the past 10 years (1965-1975) the range of
annual variation in the Christmas counts of downies
was 7-66 percent (average: 28.8) in the north, 2-38

62

percent (average: 18.2) in central Illinois, and 3-82
percent (average: 29.2) in the south. Aside from
very high peaks between 1915 and 1925 (Fig. 49),
the counts show no trend, especially since 1930. The
counts indicate little difference in population density
between the three regions of the state, agreeing in
this respect with other types of census data (Table
18). On average, a party of observers found one
downy about every 45 minutes in central Illinois,
every 49 minutes in southern Illinois, and one per
60 minutes in the north.

Food Habits

Zimmer (1921) called the downy woodpecker “a
suet gourmand,” and most of the published references

DOWNY WOODPECKER
WINTER RECORDS
DEC. 15 -FEB.1

we gt

20 oss ie al iver

@ 1950 - eo.

A 1900- 1949

mn Poke

HM BEFORE 1900

ee
é
9.

sl gisnnaton

Fig. 48.—Distribution of winter Tecords of the downy wood-
_ pecker in Illinois. Heavy horizontal lines separate the three
regions (north, central, and south) of the state referred to in
the text.

on the food of the downy in Illinois concern its at-
traction to suet, especially in winter but also at other
seasons (Brintnall (1918; Schafer 1918; Cone 1956) .
The consistent winter population of downies in
‘fields of corn stubble probably reflects the species’
predation on corn borers (Moseley 1947; Wall &
| Whitcomb 1964). Downies also commonly forage on
stalks of giant ragweed, Ambrosia trifida, (Adcock
1922; Fawver 1947a), but the food item in this case
has not been identified. Downies are important pred-
ators on the cocoons of cecropia and other Saturniid
moths (Waldbauer et al. 1970).

Rice (1946) found the dominant component of
the diet of downies in a Champaign County woods to
_be beetles and their larvae, which comprise 90 per-
|cent of the diet in fall, 80 percent in winter, 70
percent in spring, and 50 percent in summer.

Beal’s (1911) extensive study included some IIli-
nois specimens. He found that animal matter, mainly
insects, made up about 76 percent of the diet, and

vegetable matter about 24 percent in the course of
a year. Beetles, especially wood-boring cerambycids
and buprestids, were the most common food. Ants
and caterpillars were also important. A rather sur-
prising dominant food in March specimens from IIli-
nois was grasshopper eggs.

Of the vegetable food, Beal (1911) observed that
wild fruits made up about 6 percent of the total, and
mast (acorns, beechnuts, etc.) was also important.
Some corn was eaten, probably in the form of waste
grain. Conspicuous in the diet was the fruit of poison
ivy, which germinates freely after passing through the
bird, and downies may play a role in spreading this
plant.

A measure of the downy’s adaptability in foraging
is indicated in Southern’s (1966) observations of
downies feeding on dead gizzard shad in winter and
early spring in northwestern Illinois.

Specimen Data

Though two races, Dendrocopos pubescens medt-
anus and D. p. pubescens, have been ascribed to IIli-
nois (Ridgway 1914; American Ornithologists’ Union
1957), we have found no evidence of such geographic
variation among the 63 specimens (41 males, 22 fe-
males) from Illinois that we have examined. All
specimens fell within the probable limits of variation
of medianus. ‘There was great individual variation in
coloration and pattern among downies in contrast to
hairy woodpeckers. Tail barring ranged from none
(as in D. villosus) to heavy, even among specimens
from just one county (Will) though specimens with

BI)
CENTRAL

3.0

ie)

A NORTH

2.0

1.5

BIRDS PER PARTY HOUR

1.0

0.5

1900
05 15 25 35 45 55 65 75

YEAR (JANUARY)
Fig. 49.-Downy woodpeckers seen per party hour on Audu-

bon Christmas counts in the three regions of Ilinois. Each point
represents a 5-year average.

63

TasLe 18.—Winter

populations of downy woodpeckers in various Illinois habitats.

s Birds per Years Type of Region or
Babitat Se 100 nee (January) Gnias Couuty panies
Urban residential 164 0.6 1976 Strip North This paper
Urban residential 191 2.6 1976 Strip Central This paper
Urban residential 191 3.7 1976 Strip South This paper
Suburban woodlot 20 10-15 1968-1972 Map Lake (N) * Miller & Miller 1968, 1972
(avg 12.0)
_ Urban park 22 0-5 1960-1962 Map Cook (N) Greene 1960; Greene &
Greene 1962
Forest (all types, including edge) 46 9-11 1940-1941 Map Piatt (C) Johnston 1942
(avg 9.8)
Forest (all types, including edge) 65 9 1907 Strip North Graber & Graber 1963
Forest (all types, including edge) 45 4-10 1957-1958 Strip North Graber & Graber 1963
(avg 6.7)
Forest (all types, including edge) 50 2 1907 Strip Central Graber & Graber 1963
Forest (all types, including edge) 152 1-7 1957-1958 Strip Central Graber & Graber 1963
(avg 4.6)
Forest (all types, including edge) 241 3 1907 Strip South Graber & Graber 1963
Forest (all types, including edge) 211 7-11 1957-1958 Strip South Graber & Graber 1963
~ (avg 9.0)
Oak-maple forest and edge 55 4-35 1944-1975 Map Champaign (C) Kendeigh et al. 1957; Ken-
(avg 12.8) deigh & Brooks 1964a
Bottomland elm-maple forest 50 12-24 1950-1953 Map Cook (N) Montague 1950, 1952
(avg 18.5)
Grazed bottomland forest 53 13-19 1955, 1957 Map Macon (C) Chaniot & Kirby 1955a;
(avg 16.3) Kirby & Chaniot 1957
Mature bottomland forest 1,398 0-35 1974-1976 Strip South This paper
(avg 13.7)
Mature upland forest 772 0-17 1974-1976 Strip South This paper
(avg 5.6)
Shrub areas (all types, 18 11 1907 Strip North Graber & Graber 1963
including edge)
Shrub areas (all types, 74 6-15 1957-1958 Strip Central Graber & Graber 1963
including edge) (avg 10.8)
Shrub areas (all types, 33 3 1907 Strip South Graber & Graber 1963
including edge)
Shrub areas (all types, 101 5-13 1957-1958 Strip South Graber & Graber 1963
including edge) (avg 9.9)
Shrubby field and forest edge 70 4 1948 Map Richland (S) Stine & Scherer 1948
Shrubby field and forest edge 85 4 1955-1956 Map Richland (S) Shaw & Stine 1955;
Shaw et al. 1956
Shrubby field 40 (+) °-7 1958-1965, Map Lawrence (S) Scherer & Shaw 1960;
(avg 4.4) 1968 Shaw 1964
Corn stalks and stubble 602 (+) 1907 Strip North Graber & Graber 1963
Corn stalks and stubble 308 2 1957 Strip North Graber & Graber 1963
Corn stalks and stubble 360 0 1907 Strip Central Graber & Graber 1963
Corn stalks and stubble 759 (+) -1 1957-1958 Strip Central Graber & Graber 1963
(avg 0.5)
Corn stalks and stubble 282 1-5 1907 Strip South Graber & Graber 1963
(avg 2.1)
Corn stalks and stubble 277 0-1 1957-1958 Strip South Graber & Graber 1963
(avg 0.4)

aN refers to the northern region of Illinois, C to the central region, and S to the southern, as shown on winter distribution maps, e.g., Fig. 5.
> The plus symbol (+) indicates fewer than one bird per 100 acres.

TABLE 19.—Measurements of Illinois specimens of downy woodpeckers, excluding obviously worn, molting, and juve-

nile specimens.

Wing (Chord) inmm

Tail Length inmm

Region of Illinois Months Boe ef Sex

CCIE DS Range Mean sD Range Mean sD
North and Central Mar.—May 3 M 90-93 91.1 ieee 54-56 55.1 sea
North and Central Sep—Nov. i M 89-94 92.0 1.79 54-58 56.2 0.93
North and Central Dec.—Feb. 8 M 90-98 93.1 2.45 54-58 56.0 1.72
North and Central Sep.—-May 18 M 89-98 92.3 2.09 51-58 55.9 1.34
South Feb.—Apr. 10 M 89-95 91.8 1.93 51-58 55.3 2.19
North and Central Sep.—Mar. 9 F 92-95 93.8 1.25 57-61 58.3 1.17
South Oct.—Mar. 5 F 93-96 94.0 1.47 55-60 57.5 2.04
64

Rit as it

immaculate rectrices must be rare. Ventral coloration
varied from nearly clear white to strong buffy gray,
but not in any consistent geographic pattern.
‘There was no significant difference in size between
downies from northern and southern Illinois or be-
tween specimens collected in winter, spring, and fall
(Table 19). Again, this lack of differences is in con-
trast to the differences found in the hairy. Female

Fig. 50.—Black-backed three-toed woodpecker.

downies, on average, were slightly larger than males,
most notably in tail length.

We have weight data on only five specimens, all
males. February specimens weighed 24.3 (Menard
County) , 28.5 (Jersey County) , and 29.7 grams (Pope
County). A September specimen from Pope County
weighed 26.5 grams, and a November specimen from
Brown County, 26.5 grams.

65

BLACK-BACKED THREE-TOED

WOODPECKER (Picoides arcticus)
(Fig. 50 and 51)

This northern woodpecker is an uncommon
winter visitant of irregular occurrence in northern
(particularly northeastern) and central Illinois (Fig.
52). The first record for Ilinois was in 1876, when
one was found on a telegraph pole in Chicago (Cory
1909).

The black-backed three-toed woodpecker has most
often appeared in October and departed in April in
the years in which it has been reported; however, the
species has been seen as early as 12 September (Red-
field 1913) and as late as 19 May (Nolan 1957b) in
Illinois. The numbers reported each year in Illinois
since 1900 are shown in Fig. 53. There are but two
records before that time, one in 1876 and another in
1894 (Sanborn 1922b). The greatest numbers ever
reported for the state were in 1920, reported to have
been unusually warm in October and to have had a
very mild winter (Eifrig 1921 and 1922). On the
other hand, two were reported in Peoria after a
severe sleet storm (Starrett 1936) .

Hy
gy

es Bake Te on
“Woo od pecker

Pe

fa , ics y fue
he RON ce Hees
| Ve Ne NO a)
nN 1 Nine pee NG
oy * ne \
| CY 9) 40
VY { a Vy
CYR 5 |
= yo Fa BOGE.
LIBS Soe
| s SF Ue

@ 1950 -
A 1900- 1949

@ BEFORE 1900

Fig. 51.—General distribution of the black-backed three-toed
woodpecker. The range shown here may include large sections
in which populations of the species are thin or even absent
because of the nature of the terrain and lack of suitable habitat.

66

BLACK-BACKED THREE-TOED WOODPECKEI

Sept.- May Records

womay |
* > —Giunoy

TAZOWELL

ven

soaus | ON ogg

succor

wonTcour

warne

Fig. 52.—Distribution of records of the black-backed three-
toed woodpecker in Illinois. Heavy horizontal lines separate the>
three regions of the state.

Little has been written of the habits of this bird!
in Illinois. It is usually found singly or, less often, ,
with another black-back. It appears to be unwary, ,
often allowing observers to approach it closely. It!
frequently has remained in the same area for some’
days. It is said to be partial to pines and tamaracks}
(Stoddard 1920). Stoddard also noted that the black--
back had a loud and startling call, a rapidly repeated }
“teck, teck, teck.” Redfield (1913) observed that the?
pecking of the black-back was audible and distinctive. |
Lewis (1925) and Stoddard (1920) remarked that
the workings of this species on trees were character-
istic and could be used to detect its presence. Appar-
ently the bird scales the bark from trees and chisels
and bores in quite a distinctive way. There are no

data on the food of this species in Ilinois, but one»

was observed at a suet feeder (Mumford 1960). Beal

(1911) looked at stomachs from 28 specimens outside —

of Illinois and found that about 89 percent of the

food was animal matter and 11 percent, vegetable
matter. Most (64 percent) of the food consisted of
wood-boring beetle larvae, and wood-boring caterpil-
lars made up about 13 percent. Beal commented
upon the large numbers of destructive grubs that
these birds must destroy in a year’s time.

Nh
oO

ype
ow

NUMBER OF BIRDS SEEN

eS NON SS oT co =

1900 10 20 30 40 50 60 70

Fig. 53—Numbers of black-backed three-toed woodpeckers
seen yearly in Illinois, with years referring to the beginning of
the invasion, e.g., 1920 refers to the winter of 1920-1921. No
black-backed three-toed woodpeckers have been reported in IIli-
nois since 1970; however, one was found in Bettendorf, Iowa, in
1975 (Fredricksen 1976) .

IVORY-BILLED WOODPECKER
(Campephilus principalis)

There are but three old records and two records
of subfossil remains of this species for the state of
Illinois. Audubon (1831) saw the ivory-billed wood-
pecker near the confluence of the Ohio and Missis-
sippi rivers around 1825, and Ridgway thought that
he observed it in White County some 40 miles south
of Mt. Carmel circa 1852 (Ridgway 1889 and 1914;
Tanner 1942). What may have been the last record
for the ivory-bill in Illinois is found in the notes of
Benjamin T. Gault, who thought that he heard this
bird in swamps near Ullin (Pulaski County) on 15
November 1900 (Gault 1922 and unpublished notes).
Ridgway (1874a and 1874b) thought that the ivory-
bill was rare among breeding birds in the lower
Wabash Valley, and though he spent time in virgin
bottomland timber in that area (Ridgway 1872), he
made no mention of any contact with the species at
that time.

) The habitat of the ivory-billed woodpecker and
its habits were described by Tanner (1942), who
‘studied the species in Louisiana. The primary habitat
‘of this bird, according to Tanner, was virgin or ma-
ture oak-gum bottomland forest, but it also occupied
cypress-tupelo forests. The most important trees (to
‘the ivory-bill) in its habitat were sweet gum, bottom-
land red oak (Quercus nuttallii), green ash, American
elm, pecan, “hackberry” (Celtis laevigata), and over-
cup oak. All of these trees or closely related counter-
parts are found in low-lying forests in southern
Illinois, where remnants of mature oak-gum and
cypress-tupelo forests remain even now. It is thus
easy to believe the records of Audubon, Ridgway, and

|
|
|

Gault. These sight records are further reinforced by
a specimen from Forest Park, St. Louis, Missouri.
This bird, a female, number 27343, was collected on
8 May 1886, and according to Hahn (1963), is in
the Colorado Museum of Natural History in Denver.

Subfossil remains were found at Cahokia (near
Collinsville, Madison County) and near Milan (Rock
Island County) (Parmalee 1967). The tarsometatar-
sus found in a midden at Cahokia suggests that this
bird existed in this area 1000-1200 AD, especially
since the presence of suitable habitat existing there
at that time is indicated by the discovery of a large
trunk section of bald cypress at this site (Parmalee
1968). The mandibles found in a historic Sauk-Fox
cemetery near Milan are thought to have been used
as personal decoration and may have been obtained
from other localities by trade (Parmalee 1964).

This large bird required a large area (one pair
per 10 square miles) and a lot of large old trees to sup-
ply it with an ample food supply of borers and bark
beetles. The ivory-bill disappeared as virgin and ma-
ture forests were cut. A portion of its habitat was
even destroyed on the Singer tract, a wildlife sanc-
tuary maintained by Louisiana at the time the timber
was felled. Tanner's observation that greater num-
bers of woodpeckers, such as the pileated and red-
bellied woodpeckers, occurred in the mature forests
also occupied by the ivory-bill suggests that we must
take care to preserve older woodlands. The continued
clearing of bottomland forests for agricultural use
and the harvesting practices on forest land may even-
tually endanger our largest woodpecker now extant,
the pileated.

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7 :3-5.
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~—. 1947b. Bird population of an Illinois flood plain forest.

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——. 1882b. Notes on economic ornithology. Illinois State

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Fp, E. R. 1933. Bird house survey in winter. Audubon Bulle-
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= 1939. Bird houses. Chicago Academy of Sciences Leaflet
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—. 1956. Birds of the Chicago region. Chicago Academy

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[1922.| Check list of the birds of Illinois. Illinois Au-

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1917. 1916 list of Illinois nests. Odlogist 34 (5) :87.

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. 1968. Nocturnal migration in Illinois—different points

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, and R. H. Greene. 1962. Winter bird-population study.
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1910. One hundred breeding birds of an Illinois ten-
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1938. Illinois. Inland Bird Banding News 10 (3) :8.

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_. 1944. Preliminary notes on the development of nestling
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69

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1941. Notes from Dubuque. Towa Bird Life 11 (1) :15.

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1944. Observations on the courtship of four woodland

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1947. Breeding birds of the forest edge in Illinois.
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Jones, S. 1933. The season. St.
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. 1934. St. Louis region. Bird-Lore 36 (4) :247-248.

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Grange. Audubon Bul-

Illinois State Academy of

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226.

1944. Measurement of bird populations. Ecological
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1948a. Winter bird-population study. 1. Oak-maple

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1948b. Twelfth breeding-bird census. 10. Oak-maple
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1949. Winter bird-population study. 9. Oak-maple
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1960a. Winter bird-population study. 19. Oak-maple
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. 19606. 24th breeding bird census. 29. Oak-maple forest
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1973. 26th winter bird-population study. 16. Oak-
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, and L. B. Barnetr. 1967. Thirty-first breeding-bird
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, and R. D. Brewer. 1956.
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, and W. S. Brooks. 1962. Winter bird-population study.
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Twentieth breeding-bird
Audubon

, and . 1963a. Winter bird-population study. 9.
Oak-maple forest and forest edge. Audubon Field Notes
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, and 1963b. 27th breeding-bird census. 36.
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510.

, and . 1964a. Winter bird-population study. 11.
Oak-maple forest and forest edge. Audubon Field Notes
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, and . 1964b. Twenty-eighth breeding-bird census.
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, and 1965. Twenty-ninth breeding-bird census.
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, and R. J. CLEMANs. 1970. Winter bird-population study.
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, and J. M. Epcincron. 1974. Thirty-eighth breeding
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, and N. J. Forsyru. 1959. Twenty-third breeding bird
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70

, and W. Gitespie. 1955. 19th breeding bird census. 38,'
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, D. JAMes, and C. Weise. 1953. Winter bird population;

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, R. V. Kennepy, G. C. West, W. I. GILLEspIE, and J.j

OpsAHL. 1957. Winter bird-population study. 17. Oak-:

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O01.

, R. K. Srupss, and D. JAMeEs. 1951. Winter bird-popu-)
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KILHAM, L. 1958. Pair formation, mutual tapping and nest hole;
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1959. Behavior and methods of communication of)

pileated woodpeckers. Condor 61 (6) :377-387.

. 1961. Reproductive behavior of red-bellied woodpeckers, ;

Wilson Bulletin 73 (3) :237-254.

1964. The relations of breeding yellow-bellied sap-)
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520-527.

Kinc, D. B., and R. K. WINTERS. 1952. Forest resources and in-)
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KINNEY, D. F. 1868. Report on birds. Transactions of the;
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Kirsy, R., and J. CHANioT, JR. 1957. Winter bird population;
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KLEEN, V. M., and L. Busu. 1971. Spring migration. Middle-
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KnaBte, A. E. 1970. Food habits of the red fox (Vulpes fulva) )
in Union County, Illinois. Illinois State Academy of Science
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Komarek, C. V., and E. G. Wricur. 1929. Bird casualties on the:
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KRAMER, C. H. 1959. Fifty-ninth Christmas bird count. 349.)
Princeton, Ill. Audubon Field Notes 13 (2) :188-189. |

KUMLIEN, L., and N. HOLLIsTER. 1951. The birds of Wisconsin.
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KyYLerR, J. F. 1927. Bob, the redhead. Bird-Lore 29 (5) :335-338. |

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LAMPERT, C. 1922. Bird notes. Audubon Bulletin, Fall:32-33.

LAWRENCE, L. DE K. 1967. A comparative life-history study of |
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LE Baron, W. 1855. Observation upon some of the birds of
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LINCOLN, F. C, 1924. Returns from banded birds. 1920-1923.)
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. 1927. Returns from banded birds. U.S. Department of

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1939. The migration of American birds.
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Doubleday

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. 19216. Notes from the field, revised to March 15, 1921.

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. 1922. Owl kidnaps young flickers. Wilson Bulletin

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1928. Bird banding department. Wilson Bulletin 35 (2) :

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. 1925. Bird banding news—miscellaneous notes. Wilson

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1930. The mid-winter survey. Audubon Bulletin 20:

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. 1934. Illinois. Inland Bird Banding News 6 (4) :5.

. 1934-1935. Banding events of 1934. Audubon Bulletin
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Mayrtetp, H. 1951. Winter season. December 1, 1950-March
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, and . 1970. Winter bird-population study. 27.
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. and 1972. Winter bird-population study. 54.
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Monrtacur, A. C. 1950. Winter bird-population study. 12. Bot-
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1951. Winter bird-population study. 19. Bottomland

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1952. Winter bird-population study. 27. Bottomland

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1953. Winter bird-population study, 21. Bottomland
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Montcomery, A. E. 1956. Bird mortality in Elmhurst. Audubon
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Mooney, J. 1932. Notes on bird life in Lake County. Audubon
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Mosetey, M. L. 1917. Czar red-head. Audubon Bulletin, Spring
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Mumrorp, R. E. 1959a. Fall migration. August 16-November 30,
1958. Middlewestern region. Audubon Field Notes 13 (1):
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1959b. Winter season. December 1, 1958-March 31,

1959. Middlewestern prairie region. Audubon Field Notes

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1960. Winter season. December 1, 1959-March 31, 1960.

Middlewestern prairie region. Audubon Field Notes 14 (3) :

312-314.

1961. Regional reports. Nesting season. June | to
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MussetMAN, T. E. 1913. A comparative study of bird migration
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1916. Spring census and migration records for 1916.

Audubon Bulletin, Spring 1916:42.

1916-1917. Unusual birds along the Mississippi River

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1926. Quincy district, the eagles at Warsaw. Audubon

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1930. Report for central western Illinois. Audubon

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1931. The 1930 season at Quincy. Audubon Bulletin

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. 1932. The 1931 season at Quincy. Audubon Bulletin

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1933. Quincy nature diary for 1932. Audubon Bulletin

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1934. The value of project work in bird banding.

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34-1935. 1934 nature diary. Audubon Bulletin 24-
5

. 1935. Three years of eastern bluebird banding and

study. Bird-banding 6 (4) :117-125.

1937. 1936 nature diary. Audubon Bulletin 27:36-44.

Newson, E. W. 1876-1877. Birds of north-eastern Illinois. Essex
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——. 1877. Notes upon birds observed in southern Illinois
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NOLAN, V., JR. 1955. The nesting season. June 1—August 15,
1955. Middlewestern prairie region. Audubon Field Notes
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1957a. Fall migration. August 16-November 30, 1956.

Middlewestern prairie region. Audubon Field Notes 11 (1) :

28-30.

1957b. Spring migration. April 1-May 31, 1957. Mid-

dlewestern prairie region. Audubon Field Notes 11 (4):

348-350.

. 1958. Spring migration. Middlewestern prairie region.
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PARMALEE, P. W. 1959. Animal remains from the Modoc Rock
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1962. Additional faunal records from the Kingston Lake

site, Illinois. Illinois State Academy of Science Transactions

55 (1) :6-12.

1964. Vertebrate remains from an historic archaeolog

ical site in Rock Island County, Illinois. Hlinois State Acad-

emy of Science Transactions 57 (3) :167-174.

1967. Additional noteworthy records of birds from

archaeological sites. Wilson Bulletin 70 (3) :155-162.

1968. Cave and archaeological faunal deposits as indi-

cators of post-Pleistocene animal populations and distribu-

tion in Illinois. The Quaternary in Illinois. University of

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113.

1969. Animal remains from the archaic Riverton, Swan
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PATTERSON, A. J. 1923. [Bird notes.| Audubon Bulletin, Spring
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PETERSEN, P. C., JR. 1956. Unusual records from Tri-cities. Au-
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1959. TV tower mortality in western Ilinois. Audubon

Bulletin 112:14-15.

. 1964. Regional reports. Winter season December 1,

1963—March 31, 1964. Middlewestern prairie region. Audu-

bon Field Notes 18 (3) :359-360.

1966. Regional reports. Winter season December 1,
1965—March 31, 1966. Middlewestern prairie region. Audu-
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1967. Regional reports. Winter season. December 1,
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Potper, E. 1963. Starling and woodpecker interactions. Iowa
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Reuss, A. 1963. Unusuals sighted. Audubon Bulletin 128:23.

Rice, L. A. 1946. Studies on deciduous forest animal populations
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Rivcway, J. E. 1923. Olney. Audubon Bulletin, Spring 1923:
32-36.

71

1872. Notes on the vegetation of the lower Wa-
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Ripeway, R.
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= . 1874a. The lower Wabash valley, considered in its re-
lation to faunal districts of the eastern region of North
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—_—. 1874b. Catalogue of the birds ascertained to occur in
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—. 188la. An unaccountable migration of the red-headed
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—_—. 18816. A revised catalogue of the birds ascertained to

occur in Illinois. Illinois State Laboratory of Natural His-
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1887. List of birds found breeding within corporate
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1889. The ornithology of Illinois. Vol. 1. Ilinois State
Laboratory of Natural History. Reprinted 1913, Pantagraph
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1914. Birds of Middle and North America. U.S. Na-
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. 1915. Bird life in southern Illinois. ITV. Changes which
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1920. Notes from Bird Haven, Olney, Illinois. Audubon
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Roserts, G. 1922. Seven years of a food shelf. Audubon Bul-
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ROBERTSON, W., JR.. 1941a.
bird census. 9. Swampy prairie.
485.

Audubon magazine's fifth breeding-
Audubon Magazine 43 (5) :

1941b. Audubon Magazine's fifth breeding-bird census.
33. Cut-over upland forest with pond. Audubon Magazine
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1942a. Audubon magazine's sixth breeding-bird census.
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plement) .

1942b. Audubon Magazine’s sixth breeding-bird census.

22. Cut-over upland oak-hickory forest with pond. Audu-

bon Magazine 44 (5) :27 (Supplement) .

1944a. Audubon magazine's eighth breeding-bird cen-
sus. 5. Swampy prairie. Audubon Magazine 46 (5) :16
(Supplement) .

1944b. Audubon magazine’s eighth breeding-bird cen-

sus. 14. Upland oak-hickory forest with pond. Audubon
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ROBERTSON, W. B., and D. SNypER. 1948. Twelfth breeding-bird
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SANBORN, C. C. 1921. The season. Chicago region. Bird-Lore

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1922a. The season. Chicago region. Bird-Lore 24 (4) :

222-223.

1922b. Recent notes from an old collecting ground in

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, and W. A. Goetirz. 1915. A two-year nesting record in
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1918. Winter notes from Port Byron.

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. 1920. Notes from Port Byron. Audubon Bulletin, Fall

1920:21-22.

. 1921. Notes from the field revised to Dec. 15, 1921.

Audubon Bulletin, Fall 1921:39-41.

. 1922. [Winter notes.| Audubon Bulletin, Spring 1922:

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. 1923. Notes from Port Byron.

1923:37.

1933. Port Byron. Audubon Bulletin 23:56.

Audubon Bul-

Audubon Bulletin, Fall

72

SCHANTZ, O. M. 1934-1935.
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, and H. SHAw. 1960. Winter bird-population study. 20
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Scotr, T. G., Y. L. Wittts, and J. A. Etxis. 1959. Some effec
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SEGAL, S. 1960. Bird tragedy at the Dunes.
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