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Contribution No. 54
LIFE SCIENCES DIVISION
ROYAL ONTARIO MUSEUM

UNIVERSITY OF TORONTO

bE: L. SNYDER
Curator of Birds On an Unnamed
Population of
the Great Horned Owl

1961 THE ROYAL ONTARIO MUSEUM

PUBLISHED APRIL 28, 1961 BY THE ROYAL ONTARIO MUSEUM

PRINTED BY THE UNIVERSITY OF TORONTO: PRESS

On an Unnamed Population of the Great Horned Owl

For some years it has been known that a variant of Bubo virginianus,
which may be described without detail as grey in general effect but
actually patterned with fuscous-black and white, occurs occasionally
as a transient within the southern Ontario range of the nominate sub-
species. The geographic source of this variant has been presumed to be
the coniferous forest to the north. Because of its normal scarcity, hinter-
land dispersal and nocturnal habits, specimens from there have accumu-
lated slowly. Now a sufficient sample from western, northern and central
parts of the province is available not only to demonstrate agreement
with transients taken in the south but to reveal that the variant is pheno-
typic of a vast area of the more eastern interior north and that the
phenotype is as exclusive as that of any race of Bubo virginianus.

A variant presenting similar characteristics to the one in question
has been described by Bishop (1931) who proposed the name B. v.
leucomelas. This name rests on two transient specimens collected in
southern parts of Vancouver Island, British Columbia. Also Taverner
(1942, p. 243) lists 17 specimens taken at 13 separate stations from
Alaska and the Mackenzie Delta south to southern British Columbia
and Alberta which “by description . . . can hardly be separated from”
Bishop’s variant. About half of these were secured during the period of
the year when the species is sedentary and probably breeding. Thus
these are irregulars within the range of two or more geographic races
currently recognized. Taverner regarded these irregulars as hybrids
between the extensively white B. v. subarcticus' and B. v. saturatus (he

1. Manning (1952, pp. 63-64) states clearly the inapplicability of wapacuthu to the
whitish Horned Owl. Further, in this connection, Oberholser (1904; p. 192) implied
that young of the Snowy Owl are not white. This is misleading since the first natal
down of that species is white. The trivial name of Hoy (1852), subarcticus, is valid
as pointed out by Richmond (1902, p. 86). Reference to Hoy’s original description
gives assurance by the emphasis on “white and fawn colour” that he was concerned
with the Horned Owl which occupies the more northerly plains of the continental
interior (not the form described in this paper).

having proposed the relegation of B. v. lagophonus (Oberholser) to
synonymy (p. 240) ). No compact breeding range can be ascribed to
the “black and white” variants in the west. Furthermore, there is general
agreement that a geographic gap exists between the region where they
have been found and the region where a similar variant is found in the
east.

Taverner (op. cit. p. 242) in discussing the eastern variant re-
marked that it is “a very uniform and common type.” He regarded it as a
hybrid between B. v. subarcticus and B. v. heterocnemis. His descrip-
tion of it is succinct,—it is “too dark for subarcticus, too white for any
other race”... and possesses “little or no red of virginianus.”

It is obvious that there is somewhat imperfect geographic sorting of
the many forms or “phases” of this polytypic species” but never-the-less
geographic correlations are apparent and probably most recognized
populations meet the requirements of the 75 per cent rule. The fuscous-
black and white variant which occurs across 500 miles of western,
northern and central Ontario seems to display as little heterogeneity as
any. It is reasonable to conclude that since there is range interruption in
the continental interior, B. v. subarcticus intervening, the sporadically
distributed counterparts of this population which occur in the far west,
cannot be considered the same. Each perhaps represents a similar but
separate biological phenomenon, the results being the same except that
in the east the variant has acquired homogeneity over a considerable
range. It behaves as would be expected of a geographic race in the
display of intergradation in border areas where it meets other recog-
nized races. For example the whiteness and yellowness of individuals
occupying the region along the more northern border between Ontario
and Manitoba and in northeastern Manitoba indicate intergradation
with B. v. subarcticus. Toward the south in this longitude a lessening of
whiteness and a darkening of yellowness indicates a trend toward B. v.
occidentalis. Other individuals from the southern part of this region
display reddish brown tendencies characteristic of the nominate race,
the range of which is contiguous in Minnesota. It is pertinent to remark
here that this is the general region where the ranges of geographic races
of many species of birds meet and produce maximum mixtures. It is
where plains meet forest, where boreal islands are relict though climate
is moderate, where “east meets west and north meets south.”

Concerning the rare irregulars found within the range of the form
under discussion, Taverner (op. cit. p. 237) lists a specimen, taken on
June 20, at Kapuskasing, Ontario, as B. v. virginianus. A December

2. For example, Taverner found virginianus-like specimens from southern Alberta and
British Columbia, including Vancouver Island (p. 243).

specimen (R. O. M.) from Swastika, Ontario, is likewise readily re-
ferable to that form. It is possible that the range of the nominate race
extends north through the eastern clay-belt thus intercepting an east-
ward extension of the “black and white” population into northern parts
of southern Quebec. This is still to be determined. Another apparently
irregular is that of Taverner (Joc. cit.) who lists a specimen from Moose
Factory in the Carnegie Museum, taken on July 12, as B. v. subarcticus.
Although most museum specimens of this form under discussion have
probably been referred to B. v. subarcticus, Taverner distinguished
them, as hybrids.

Some fifty mature individuals in the R. O. M. represent both birds
established in the region outlined and transients collected more im-
mediately beyond. The writer believes that this collection represents an
unnamed geographic race for which the following name is proposed:

BUBO VIRGINIANUS SCALARIVENTRIS, subsp. nov.

Type

Adult female, R. O. M. no. 75245; collected February 26, 1948, at
Elsas, on the upper Kapuskasing River, in Algoma District, Ontario, by
D. G. Waldriff, District Conservation Officer, Ontario Department of
Lands and Forests. Sex determination by dissection and measurements
from the specimen in the flesh were made by C. E. Hope.

Measurements of the type
Wingspread 1340 mm.; length 585 mm.; weight 1155 gms.

Subspecies characters

Dorsally, the normally exposed portions of the feathers fuscous to
fuscous-black densely but narrowly vermiculated with white; the under-
colour, or basal portion of the feathers, most frequently exposed on the
occiput, hind neck and fore-back, approximately clay-colour. Ventrally
with fuscous-black (anteriorly) to fuscous (posteriorly) transverse
bars, comparatively regular in outline and nearly as wide as the inter-
vening white spaces except on the under tail coverts. Usually with little
or no pattern of finely vermiculated spots superimposed over the barred
pattern. Facial disc pale grey, sometimes slightly stained with warm
colour. Feet soiled white, usually sparsely, vaguely and irregularly
marked with drab. Distinguished from B. v. subarcticus by dark colour
predominating over white and yellow dorsally and by the broader, more
regular and darker bars ventrally. In broad terms, the form can be
described as more coldly grey with bolder bars below. B. v. subarcticus

5

is extensively white and tawny with more vague and sparse dark mark-
ings below. Distinguished from the nominate subspecies by the general
absence of rufous in the plumage, the greyness of the dorsal area and
the virtual lack of large, vague, finely vermiculated spots superimposed
over the barred ventral pattern so characteristic of B. v. virginianus.

Measurements

(Racial intergrades not included. Wingspread, length and weight
measurements made in the flesh by the preparator; others by the writer.
Bracketed figure = number of measurements, this followed by mini-
mum and maximum; the mean in parenthesis. )

é 6; wingspread [5] 1230-1300 (1280), length [8] 518-560
(540), chord of wing [8] 328-355 (343), tail, from external point
between central feathers [8] 191-212 (200), culmen, from cere [8]
25-30 (26.7), weight [1, summer] 1275, [4, fall] 1110-1340 (1238),
[2, winter] 1239-1418 (1329).

2 2; wingspread [18] 1295-1410 (1361), length [22] 555-600
(578), chord of wing [23] 350-380 (362), tail, from external point
between central feathers [23] 205-234 (216), culmen, from cere [23]
28-—32.5 (30.9), weight [1, spring] 1410, [6, fall] 1120-2145 (1580),
(12, winter] 1155-2110 (1745).

Range

From near the boundary of Manitoba in northwestern Ontario (and
probably in northern Manitoba), east over the Precambrian Shield to
near the Ontario-Quebec border (and probably beyond*), north to the
Albany River and south to Port Arthur and approximately the Sault
Ste. Marie-Lake Nipissing line. Periodically transient south to Lake
Ontario, rarely beyond (Coldstream, Middlesex County) and wander-
ing east to Brador Bay, Saguenay County, Quebec (Taverner, op. cit.,
p. 242)* and west to The Pas, Manitoba. Individuals referable to this
form are to be expected in northern Minnesota and northern Michigan.

3. There are transient specimens in the R. O. M. which the writer interprets as inter-
grades with B. v. heterocnemis.
4. Taverner’s subarcticus x heterocnemis = B. v. scalariventris.

6

Literature Cited

BISHOP, LOUIS B.
1931 Three apparently undescribed owls. Proc. Biol. Soc. Wash. vol. 44, pp. 93-94.

HOY, PHILO R.
1852 Description of two species of owls, presumed to be new, which inhabit the

state of Wisconsin. Proc. Acad. Nat. Sc. Philadelphia, vol. 6, no. 6, pp.
210-211.
MANNING, T. H.
1952 Birds of the west James Bay and southern Hudson Bay coasts. Nat'l. Mus.
Can. Bull. no. 125, pp. 1-114.
OBERHOLSER, HARRY C.
1904 A revision of the American Great Horned Owls. Proc. U.S. Nat’l. Mus., vol.
27, no. 1352, pp. 177-192.
RICHMOND, CHARLES W.
1902 The proper name for the Arctic Horned Owl. Proc. Biol. Soc. Wash., vol. 15,
p- 86.

TAVERNER, P. A.
1942 Canadian Races of the Great Horned Owls. Auk, vol. 59, no. 2, pp. 234-245.

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