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RESPONSE OF JUVENILE RAFTORS
TO DDT IN THE DIET;

JOHN C. SEIDENSTICKER IV

STATE DOCUMENTS COLLECTIOfI

DEC r,o 1985

MONTANA STATE LIBRARY;

1515 E. 6th AVE.
HELENA, MONTANA 59620

B. A. Iftiiversity of Montana, I966

UNIVERSITY OF MONTANA

1968

JUN 3 '*-1f92

MONTANA STATE LIBRARY

S639.9 Thesis SEIDENSTICKER 1966 c.1 Se
Response of juvenile raptors to DDT in t

3 0864 00056661 5

RESPONSE OF JUVENILE RAPTORS
TO DDT IN THE DIET

JOHN C. SEIDENSTICKER IV

B. A. University of Montana, 1966
Presented in partial fulfillment of the requirements for the degree of
Master of Science in Wildlife Technology

UNIVERSITY OF MONTANA

1968

Approved by:

Chairman, Board of Examiners

Dean, Graduate School

Date

Seidensticker, John C, IV, M. S., December 1968 Wildlife Technology-
Response of Juvenile Raptors to DDT in the Diet. (viii, 7^ pp. )
Director: John J. Craighead

An investigation was conducted during the spring and summer of
1967 in south- central Montana to obtain information on the response
of Juvenile red- tailed hawks (Buteo jamaicensis) and golden eagles
(Aquila chrysaetos ) to DDT in their diet. The experiments were
designed to: l) measure the accumulation of DDT residues in nest-
ling hawks and eagles, 2) measure storage and loss of DDT residues
in post- fledging hawks, and 3) determine the effects of feeding
DDT on their growth, development and behavioro

Nine red-tailed hawks and 1 golden eagle were fed 20 mg technical
grade DDT per kg body weigh^ as nestlings. At fledging, 3 hav;ks
and the eagle were sacrificed and the remaining hawks were retained
in captivity for hO additional days. Three of the post- fledging
hawks were fed DDT at the nestling rate while the remaining hawks
were fed no DDT. The chemical analysis of brains, breast muscles
and livers from these birds showed:

1) The nestling hawks and eagle accumulated substantial levels
of DDT and its metabolites;

2) Post-fledging hawks fed DDT as nestlings and for ^0 addition-
al days contained the same levels of DDT and its metabolites
as did nestlings ;

3) Post-fledging hawks fed DDT as nestlings and DDT free diets
for ho additional days contained only one-fourth as much
DDT and its metabolites as did nestlings.

These experiments indicated a difference in the accumulation of DDT
and its metabolites in young raptors during different stages in
their grofrth and development and that post-fledging juvenile hawks
have the ability to eliminate DDT and its metabolites rather rapidly
while on DDT free diets «

More DDT residues accumulated in the brains, breast muscles, and
livers of diseased nestling hawks than in the brains, breast muscles
and livers of healthy nestlings. DDT is retained in the tissue of
juvenile red-tailed hawks longer than DDT+DDD, One of six red-tailed
hawks fed DDT during the nestling period failed to learn to feed it-
self during a ifO-day post-fledging period in captivity indicating
that DDT might affect the behavior of developing hawks. DDT at the
dosage used in these trials did not affect the growth of red-tailed
hawks or golden eagles.

PROJECT FTMNCING

Financial su-oport for this project was supplied ty U. S. Fish
and Wildlife Service Contract No. IO-I6-OO8-718 and by the Montana
Cooperative Wildlife Research Unit; U. S. Fish and Wildlife Ser-
vice, University of Montana, Montana State Fish and Game Department,
and Wildlife Management Institute cooperating.

PT.K/VSE NOTE; This dissertation is not a publication, and no portion
herein may be quoted without express permission of the author, the
Department of Zoology, and the Montana Cooperative Wildlife Research
Unit.

■

ACKNOWLEDGEMENTS

During the "eagle study" Harry Reynolds and I worked together
in a team effort collecting data on our separate research projects.
If this=",spirit of cooperation had not existed, my study would have
been severely handicapped.

I deeply appreciate the assistance of Dr. John J. Craighead
for his help and guidance throughout this study. I also wish to
thank Drs. D. A. Jenni, P. L. Wright, and B. W. O'Gara for their
helpful suggestions.

For advice and assistance, I wish to thank the following:
Rand Bradley, Mrs. Alvina Barclay, Dr. F. C. Craighead, Jr., Andy
Dyka, Dr. J. J. Hickey, Tom Mussehl, Dr. J. C. Seidensticker, and
Jay Sumner.

Special thanks go to my wife, Sue, for her assistance in the
field and her encouragement and support.

J. C. S<

-iii-

•

^ TABLE OF CONTENTS

Page

^ INTB.ODUCTION, 1

STUDY AREA .,o . 7

Geographic location, , » o.,„ , 7

Vegetation 9

, Land use , 12

METHODS AMD PROCEDURES ....... ll+

Experimental procedure II4

^ DDT dosage. 15

Care of captive raptors. «..,..... 17

Collection and analysis of tissue, , , 17

, - RESULTS AND DISCUSSIONo 18

Insecticide Residues and Background Levels. 18

-ft

* " Red- tailed Hawk Feeding Trials. 21

DDT accumulation in nestling hawks 21

Storage and loss of DDT by captive hawks. ................. 22

Changes in DDT metabolites. 2k

DDT residues in hawks dying from "natural" causes.....,.,, 25

Growth and development 29

^ Golden Eagle Feeding Trials ^2

DDT accumulation in nestling eagles h2

Growth and development k3

General Discussion ^8

SUMMARY. 52

LITERATURE CITED 5^

APPENDIX A - THE BIOPSIC PROCEDURE 58

The Biopsy ...» o.,.. . 59

Procedure , . . . , 59

^ Results and discussion 62

The Anesthetic 6U

Procedure .........<..... 6k

Results and discussion , 65

^ APPENDIX B - ANALYTICAL METHODOLOGY 71

LIST OF TABLES

Table Page

1. Climatological summary, I967 11

2. Summary of DDT intake I6

3. Organochlorine insecticide residues found in south-
central Montana » • • . 20

k. Accumulation of DDT residues (DDT, DDD, DDE) in nestling

red- tailed hawks 21

5. Storage and loss of DDT residues (DDT, DDD, DDE) in
captive red-tailed hawks 23

6. Loss of DDT residues (DDT, DDD, DDE) by post-nesling,
captive red-tailed hawks on diets devoid of DDT. , 23

7. Total DDT residues (DDE, DDD, DDT) in tissue of experi-
mental hawks with the proportion of DDE and DDD+DDT ex-
pressed as a percentage of the total 27

8. Comparisons of DDT residues (DDE, DDD, DDT) in the
brains of red-tailed hawk nestlings dying of pneumonia

and those sacrificed at the end of the nestling period.. 28

9. The development of the juvenal plumage and other main
points in the physical development of red-tailed hawks

and golden eagles 37

10. DDT residues (DDE, DDD, DDT) in control and experimental
golden eagles and red-tailed hawks at the end of the
nestling period • hh

11. Water, lipid, and organochlorine insecticide contents
in whole pectoralis ir.uscles and small muscle samples
(biopsies) which were taken from pectoralis muscles

of fledgling red-tailed hawks. .......................... 63

12. Dosage and results of administering Equithesin intra-
muscularly to some different species of birds. 66

13. Dosages of Equithesin for some avian species.... 69

ih. Analytical results when the same tissue was analyzed by

two different methods. 7h

-vi-

LIST OF FIGURES

Figure ■ • Page

1. Jfep of the south-central Montana study area. , « 8

2. Total DDT residues (DDT, DDD, DDE) in experimental
red-tailed hawks , o.o .... o » ...... oo ...... o o ... . 26

3. Growth of male red-tailed hawk nestlings as shown by-
changes in weight oo...........<........o.o..o». ........... 32

h. Growth of female red-tailed hawk nestlings as shown

by changes in weight. ................. .....o....... ...... 33

5. Growth of the right foot pad. ............................ 35

6. The length of the seventh right primary of nestling,

male red- tailed hawks. .................................... 38

7. The length of the seventh right primary of nestling,

female red-tailed hawks 39

8. The length of the sixth right rectrix of nestling,

male red-tailed hawks. ..,.,....„ ........... ............. .

9. The length of the sixth right rectrix of nestling,
female red- tailed hawks ........ .

10. Growth of female golden eagle nestlings as shown by

changes in weight ,.«....... .......o,..oo.o.«o............ ^7

11. The length of the seventh right primary of nestling,

female golden eagles . o.. ........ ........„...<> ......... , ^9

12. The length of the sixth right rectrix of nestling,

female golden eagles . ................... ..... 50

13. The bxopsy. o.ooaoo.oo....oo..oo.oooooaoo.9o.. ......««...« 61

-Vll-

•

LIST OF PLATES

Plate

1. Nestling red-tailed hawks.

2. Nestling golden eagles. o„ .

-viii-

INTRODUCTION

In the IMited States and in Europe some raptor populations have
recently suffered serious declines. Ratcliffe (1963) 1965 ) found
that in the past 13 years there had been a rapid decline in both
numbers and productivity of the peregrine falcon (Falco peregrinus ) .
Similar declines in some Scottish golden eagle (Aquila chrysaetos )
populations have also been reported. (Lockie and Ratcliffe, 196^+)-
Cramp (1963) outlined the decline of the sparrow hawk (Accipiter
nisus), merlin (Falco columbanius ) , and kestrel (Falco tinnunculus)
in England. Prestt (1965? I966) reported that the buzzard (Buteo
buteo). sparrow hawk, merlin, kestrel, tawny owl (Strix aluco), and
barn owl (Tyto alba) have declined. The number of sparrow hawks,
kestrels, and barn owls has dwindled rapidly; the buzzard, merlin
and tawny owl have been affected less severely,

Sprunt and Ligas (1963) have reported serious declines in bald
eagle (Hallae bus leucocephalus ) populations occurring in parts of
the United States and Cottam et al.. (1961) cited observations on
the decline of the golden eagle. Breeding populations of osprey
(Pandion haliaetus ) on the eastern coast have diminished. For ex-
ample, eight active nests were reported from nine areas in southern
Cape May County, New Jersey, in I963 where 28 active nests were re-
ported in 1937 (Schmid, I966). Ames and Mersereau (196U) found that
the number of nesting pairs of osprey in a Connecticut River colony
had decreased at a mean annual rate of 31^ since i960. In recent
years the peregrine falcon has experienced catastrophic population
declines over much of Worth America (Hickey, in press).

The rapid decline of some raptor populations has emphasized the
need for establishing population norms » In 1963 a study was hegun
on the dynamics of a breeding golden eagle population in south-central
Montana. In summarizing the results of the study, McGahan (1966,
1967, 1968) emphasized the value of ecological data in evaluating
the effect of future environmental changes on golden eagle popula-
tions,

A second 3-year investigation was launched in I965 (Reynolds,
in prep. ). This constituted Phase II of the long-term golden eagle
population study directed and supported by the Montana Cooperative
Wildlife Research Unit. A significant drop in the eagle productivity
was detected during the first field season (1965); the next 2 years
were spent gathering data on productivity, nesting density and
food habits for comparison with similar data gathered earlier by
McGahan on the same study area. ' ' '

Declines of raptor populations have often been linked with
environmental contamination by toxic chemicals. In Europe, where
this condition has been investigated in detail. Cramp (1963) found
pesticide residues in 13 different raptor species in Great Britain,
Sweden, and Holland and he concluded that pesticides were the
major cause of the declines. Lockie and Ratcliffe (196U) attri-
buted the decline of a Scottish golden eagle population to increased
use of persisting toxic chemicals on the landscapco Ames (1966)
found a decreased hatchability of osprey eggs with increased

environmental contamination by DDT l/. The peregrine falcon decline
in Britain was analyzed by Rat cliff e (1963:86) who stated that "Cir-
ciimstantial evidence pointed strongly to agricultural toxic chem-
icals as the cause of decline, through contaminating prey taken by
peregrines, which then accumulated the poison indirectly, " In the
Netherlands, birds of prey and fish-eating birds were collected for
analysis. Many of these specimens contained large amounts of chlor-
inated hydrocarbon residues (Koemen and van Genderen, 1966)0 Dust-
man (1966) reported that of the 68 bald and golden eagles collected
throughout the United States, all but one bald eagle from Alaska
contained DDT residues. Cade et al. (1968) and Enderson and Berger
(1968) have found high levels of chlorinated hydrocarbon residues in
arctic peregrines.

The presence of chlorinated hydrocarbon insecticide residues
in the tissue of birds of prey, which are at the top of the biotic
pyramid, is well documented but the build-up of residues in these
birds is a biochemical process that is by no means understood (Hickey,
1966). The occurrence of organochlorine insecticide residues in
predatory birds which do not normally have direct access to pesti-
cides has resulted in a shift of research emphasis from toxicologi-
cal studies on single species to studies involving entire ecosystems
(Moore, I967). Persistent, fat-soluble chemicals such as the organo-
chlorine insecticides are transferred along food chains. Persisting

1/ The chemical names of insecticides can be found in Menzie

chemicals are sometimes concentrated at successive trophic levels in
the biotic pyramid until they become toxic to the carrier. This
phenomenon of delayed expression and biological concentration of
persistent pesticides in both terrestrial and aquatic ecosystems is
well documented (summarized by Rudd, 1961+:250-267)<.

The vast quantities of organochlorine insecticides that have
been dispersed over the landscape and the persistent nature of these
insecticides have made them part of the geological and chemical
cycles of the earth (Woodwell, 1967). The fact that persistent
pesticides have become important new ecological factors in the en-
vironment was emphasized in the recent report by Wurster and Wingate
(1968). These investigators found that organochlorine insecticides
are widespread within oceanic organisms to the extent that the ex-
istence of pelagic species such as the Bermuda petrel (Pterodroma
cahow) is threatened.

Despite considerable research, the mode of action of the organ-
ochlorine insecticides is incompletely understood. It has been postu-
lated that continued ingestion of sublethal amounts of organochlorine
insecticide residues by avian predators may result in reduction of
clutch size, hatchability of eggs, number of young surviving, or a
combination of these, Hickey (1966) believes that in some avian popu-
lations these result in fewer young birds to replace the adults that
are gradually disappearing.

To evaluate possible effects of environmental contamination by
persisting toxic chemicals on raptor popxilations, a survey of chlor-
inated hydrocarbon residues in the body tissues and eggs of golden

-5-

eagles and other large raptors and their prey species in south-
central Montana was conducted by Rejmolds (in prepo )o

The effect of sublethal levels of organochlorine insecticides
on nestling and fledgling birds under field conditions has been
studied very little. The nestling raptor is characterized during
its development by rapid growth dependent upon the ingestion of
large quantities of foodo I postulated that during this period of
development an altricial bird might be more susceptible to toxic
chemicals than at any other time in its life. Lacking specific in-
formation on the ways sublethal environmental levels of organo-
chlorine biocides might affect nestling raptors, a study was designed
to investigate possible effects of DDT on nestling raptors from hatch-
ing until well after fledging.

Recently serious doubts have been raised concerning the projec-
tion of the resTilts of laboratory pesticide studies to field con-
ditions (Moore, I965; Stickel £t alo , 1965)« With this in mind, pre-
liminary field techniques were developed and time schedules were
devised during the 1966 field season for conducting studies on the
response of juvenile raptors to DDT under field conditions. With
this preliminary field work as a background, a series of DDT feeding
experiments in the field, using sublethal dietary levels of DDT, was
conducted during the spring and summer of 1967<.

The specific objectives of this study were: l) to conduct feed-
ing trials with nestling red-tailed hawks (Buteo jamalcensis) and
golden eagles and measure accumulation of DDT residues, 2) to mea-
sure storage and loss of DDT residues in post- fledgling red-tailed

-»

-6-

hawks^ and 3) to determine the possible effects of feeding DDT on
growth, development, and behavior.

STUDY AREA

Geographic location

The intermontane valleys in the vicinity of Livingston, Mon-
tana, will be referred to throughout this report as the "study area"
(Fig. l). Nearly 80% of the 35-township golden eagle study area
(Area A) used by McGahan (1968) and Reynolds (in prep. ) is included
in this area.

Topography

The Yellowstone River and its major tributaries (the Shields
and Boulder Rivers) constitute the major watershed in the study area.
The Yellowstone River flows from the southern mountaino'us regions
northward through Paradise Valley, around the northwest flank of the
Absaroka Range, and thence eastward. From the Crazy Mountains, the
Sheilds River flows south and meets the Yellowstone near Livingston;
the Boulder River forms in the Absaroka Range and flows northeast
until it joins the Yellowstone River east of the study area near
Big Timber. Numerous smaller tributaries enter these major streams
throughout the area.

Elevations on the study area range from 1+, 000 feet along the
Yellowstone River to more than 10,000 feet in the Absaroka, Bridger,
Crazy, and Madison Ranges which bound the area. Throughout the area
there is a transitional foothill zone between river bottoms and
mountains which is characterized by buttes, escarpments, and ravines.
McGahan (1966) calls this transition zone a typical golden eagle
nesting habitat.

_7.

Figure 1. Map of the south- central Montana study area

SCALE: 1 INCH = 6 MILES

The complex pattern of vegetation in south-central Montana
appears to be the result, as in other areas, of various environ-
mental factors (moisture, soil, fire, etCo )» At the lowest eleva-
tions in the intermontane valleys a majority of the flood plain and
riparian communities are dominated by Cottonwood (Populus spp. ) and
willow (Salix spp,, )» Quaking aspen (Populus tremuloides ) groves
occur on river flood plains only at higher elevations. Cottonwood
and quaking aspen dominate the majority of the foothill riparian
communities. However, Engelmann spruce (Picea engelmanni) and
Douglas fir (Pseudotsuga menziesii) are prominent in foothill flood
plain and riparian communities on the east side of Paradise Valley.

Much of the tillable area on lower slopes and in the creek
and river flood plains has been planted to alfalfa, "wild hay", and
graino Vegetation on the remaining lower slopes consists of wheat-
grasses (Agropyron sppo ) , fescues (Festuca spp. ), needlegrasses
(Stipa s^o ), junegrass (Koeleria cristata), and other grasses and
forbs. The grasses and forbs are interspersed in some areas with
big sagebrush (Artemisia tridentata). In the foothill zone limber
pine (Pinus f lexilis ) and juniper (Jxmiperus scopulorum) are found
on some sites. " '-

Douglas fir, together with lodgepole pine ( Pinus contorta), is
found above the foothill zone. Meadows of various sizes are inter-
spersed in this zone. At these higher elevations aspen, Engelmann
spruce, alder (Alnus spp. ) , and willows are dominant in the riparian
communities. Lodgepole pine continues to be abundant to timber line.

^ -10- '
The alpine zone is characterized by boulder fields, rocky
ledges, and scree slopes with little soil development. Small areas
dominated by mat- and cushion- forming plants as well as some per-
ennial grasses are present.

Climate ' ' ,

Altitude, latitude, mid-continent position, and mountain bar-
riers all influence the climate in the study area (Shearer, 1958 )•
Yearly maximum and minimum temperatures vary greatly. On the aver-
age, the coldest month is January and the warmest is July. The
average January temperature (approximately 22°Fo ) in the upper
Yellowstone River Valley is higher than that recorded for most
other sections of tfontanao Annual precipitation on the area is
13-1^+ inches,

A simimry of climate logical data for the 1967 study period is
presented in Table lo Mean temperatures on the study area during
the study period for I967 were cooler than normal, while precipita-
tion ranged from below normal in February, May, and August to
above normal in Nferch, April, and July, More than twice the aver-
age rainfall was recorded during June. .

• . ■ ■ _ •■ f

Fauna ' '

The species and general distribution of the mammals in south-
central Montana has been outlined by Hall and Kelson (1959) •>
More recently Hoffmann and Pattie (1968) have compiled a detailed
account of the status and distribution of Montana mammals. Richmond
and Knowlton (189^+) and Saunders (1921) have reported the status of

Table 1, Cliinatological Summary, I967*

Air temperature, oF

Mean Mean Precipitation
daily daily Mean of daily Total inches
Month Ifex. Mino max. min. maXo and min. of water

February

ho.6

2k, 0

32.3

.16

March

-7

38.5

17.3

27.9

2.21

April

1^9.3

27.9

38.6

1.60

May

60.8

37«0

1+80 9

1.90

June

31+

67.0

k6,0

56. 5

. 5.30

July

81.8

51o5

660 7

2.98

August

84.85

1+8.9

66.7

*Data taken at the Livingston Airport in the approximate
center of the study area (U.S. Dept. Comm., 1967)

-12- \- ..

avian species in the area.

An effort was made during this study to determine the present
breeding status of the birds of prey (Falconiformes and Strigi-
formes) present in the study area. Nesting records were obtained
for the red- tailed hawk, golden eagle, goshawk (Accipiter gentilis).
Cooper's hawk (A. cooperii), sharp-shinned hawk (A. striatus ),
Swainson's hawk (Buteo swainsoni), ferruginous hawk (B. regalis),
marsh hawk (Circus cyaneus ) , prairie falcon (Falco mexicanus),
American kestrel (Fo spaverius ) , great horned owl (Bubo virginianus ) ,
long-eared owl (Asio otus), and short-eared owl (Asio f lammeus ) for
a total of 13 species. In addition, Mr, J., Sumner (per. comm. )
reports that the peregrine has nested on the study area in recent
years. Other species which were occasionally observed in the area
are the turkey vulture (Cathartes aura ) , bald eagle, osprey, and
saw- whet owl (Aeolius acadicus ). During early April rough-legged
hawks (Buteo lagopus ) were commonly seen in the northern part of
the study area prior to their departure for northern nesting areas.

Land use

The economy of south- central Montana is based primarily on
agriculture. The statistical analysis of agricultxire prepared by
various governmental agencies is based on the county unit. The
following discussion is based, therefore, on the statistics from
Park County where the majority of the raptor eyries used in this
inquiry were located.

The U, S, Department of Commerce (1966) reports that during
the 5-year period, 1959-196^+, the total acreage in farms and ranches

-13- : • : . .

remained relatively constant at ^2% of the land area or 881,000
acres. During this same period, the number of farms and ranches
has dropped from k38 to k20, and the average farm and ranch has in-
creased in size from 1,926 acres to 2,073 acres. In 1959* ^1*075
sheep (including lambs) were headquartered on 163 ranches, while in
196U, 19,636 sheep (including lambs) were based on 101 ranches. In
1959* 2k,3hO cattle (including calves) were based on k02 ranches
while in 19^+6, 32,071 cattle (including calves) were based on 379
ranches. The cropland harvested during this period increased from
54,000 to 59,000 acres. The main source of farm income is livestock
and livestock products with the sale of field crops being an import-
ant second.

While the above data do not cover the same period as this study,
the general land use trends in the area are shown. The trend of
land ownership in the area is toward fewer and larger farms and
ranches, and cattle have become the most important livestock species.
U. So Department of Commerce (1966) data indicate that the increase
in harvested croplands has been accompanied by an increased use of
agricultural chemicals of all tjrpes.

IffiTHODS AHD PROCEDURES

Locating nests ~ '' , • .

Formerly active golden eagle eyries in the vicinity of Livings-
ton were checked early in the season. Two eyries were selected for
use in the DDT trials o By following the procedures outlined by the
Craigheads (1956; 196-199)> 38 active red- tailed hawk nests were
located prior to and during the incubation periods Thirteen hawk
nests were selected for the experiments <> To minimize nest loss
through desertion and chilled eggs, disturbance of raptor nests
prior to and during the incubation period was kept at a minimum.

Experimental procedure

The experiments were of two types ; those measuring the effect
of DDT on nestling raptors and those measuring the storage or loss
of DDT in the raptors during the nestling period and for a time
after they left the nesto Both experiments utilized the same birds.

Newly hatched nestlings from I3 red-tailed hawk nests and two
golden eagle eyries were selected for the feeding trials. From
these nestlings, 11 hawks and 1 eaglet were placed on diets con-
taining DDTc The remaining nestlings, ih hawks and 2 eaglets acted
as controls. Twelve hawk nests and 1 eagle eyrie contained 2 nest-
lings each; 1 hawk nest and 1 eagle eyrie contained 1 nestling each.

Each nest was visited once every h days during the nestling
period. Every effort was mde to keep the experimental situation
as natural as possible except for the experimental feeding of DDT.
The birds remained undisturbed in their nests except for weighing.

-II+-

' ' ' ' ■ ' ' '

measuring, and feeding. The parent birds returned regxilarly with
food. Thus, the natural diet was supplemented with a ration of
DDT once every h days for those birds on DDT diets. Control birds
were weighed and measured but not fed DDT.

At kO days (the approximate fledging time for red- tailed hawks),
one control hawk and 3 hawks on DDT diets were sacrificed. The re-
maining control hawks were biopsied, banded and released. Six hawks
fed DDT in the nest were kept in captivity for an additional kO days.
Three of these were continued on DDT diets for the second period.
The other three were placed on diets which contained no DDT. At
the end of this second period all birds were sacrificed including
one control bird that had been retained in captivity but never fed
DDT.

Two eaglets were sacrificed after 60 days (the approximate
fledging time), A biopsy was taken from the third eaglet, a control,

and it was banded and releasedo

DDT dosage '

DDT was selected for use in this study because of its importance
in environmental contamination and the considerable literature avail-
able from controlled laboratory experiments.

Technical grade p, p' isomer of DDT was dissolved in vegetable
oil, inserted into noo 0 gelatin capsules, and administered orally
to experimental birds « The dosage used was 20 mg DDT/kg body weight
once every h days. Thus, the DDT application approximated periodic
meals which were highly contaminated with DDT (cf . Stickel et al. ,
1966a) o The dosage was based on body weight to compensate for the

-16-

weight change and increased food consumption by nestlings as they
grew. It is not known to what extent the different metabolic
rates of the two species affected the intake of DDT but for com-
parative purposes, the same dose was used for both the golden
eagle and the red- tailed hawk,

A summary of total DDT intake is shown in Table 2.

Table 2, Summary of DDT intake

Bird
no. *

Days

test

DDT dosage #

Nestling
(mg)

Post-
nestling
(ing)

Total

Killed
"or U-i.
died

Red-tailed hawk;

121

159

Ikl

Ihl

118

217

335

125

185

310

121

205

326

0**

17k

122

0**

122

Golden

eagle :

758

# The dosage used was 20 mg DDT/kg body wt once every h days

* Does not include 1 hawk which was fed DDT but was killed by
a great horned owl early in the experiment

Nestling kept in captivity for kO days on diets devoid of DDT

-17-

Care of captive raptors

During the coiarse of this study, the Craigheads' procedure
(1956: 312=313) for maintaining captive raptors was followed. All
"birds were equipped with jesses, swivel, and leash and placed on
perches. Every bird was well "manned" and they were exercised per-
iodically "by flying them from the perch to the gloved hand.

Collection and analysis of tissue

Tissues for pesticide analysis were obtained using a biopsy
technique (Appendix A) or by killing the raptoro The biopsy tech-
nizue enabled the researcher to collect muscle and adipose tissue
from living birds of prey, thus reducing the number sacrificed.

When collected, large tissue samples were placed in separate,
double, polyethlene bags and labeled. The small samples collected
by biopsy were placed in clean, screw-top 5 ml vials. All samples
were frozen immediately after collection and stored in a freezer
pending analysis.

The tissues collected for analysis were shipped via air express
to Wisconsin Alumni Research Foun^tion, Ifedison, Wisconsin, and all
residue levels reported here were determined in their laboratory
under the direction of Fo B» Coon. Samples were analyzed for organo-
chlorine insecticide residues with a gas chromatograph (Aijpendix B).

RESULTS AM) DISCUSSION

Insecticide Residues and Background Levels

Before results of the tissue analyses are discussed, the source
of the organochlorine insecticide residues found in hawks and eagles
on the study area will be reviewed.

DDT is changed to a series of metabolites in animal tissues.
While these metabolites differ in toxicity, they are similar to one
another in their chemical and physical properties. Studies on the
pathway of DDT metabolism in animal tissue indicates that DDT is
converted primarily to DDE and DDD. DDD is not converted to DDE,
nor is DDE converted to DDD. The only metabolites of DDT found in
this study were DDE and DDD but other metabolites do exist. DDT
and DDD are both present in technical grade DDT (Metcalf, 1955) and
Reynolds (in prep. ) reports that both DDT and DDD were marketed as
insecticides in the study area.

In addition to DDT (and its metabolites) residues of other
organochlorine insecticides (dieldrin and heptachlor epoxide) were
found in raptor tissue. Aldrin is converted to dieldrin in animal
tissue (Menzie, I966). In south-central Montana dieldrin is used
regularly as an insecticide but Reynolds (in prep. ) reports that
little aldrin has been used in recent years.

Both heptachlor and chlordane are used as insecticides in south-
central Montana (Reynolds, in prep»). Commercial chlordane is a
mixture of at least five compoimds including heptachlor which is
converted to heptachlor epoxide in animal tissue (Menzie, 1966).

-19-

The hawk and eagle nestlings which were used in these trials
remained in their nests throughout the nestling period and the nest-
lings were therefore subjected to background levels of organochlorine
insecticide residues through the nattaral food. Reynolds (in prep. )
measured the level of contamination by determining what organo-
chlorine insecticide residues were present in the tissue of the
raptors xinder study and their major prey species (Table 3). The
average residual level of organochlorine insecticides in the muscle
of prey species was less than 0.2 ppm. The average level in the
breast muscles of fledling red- tailed hawks was 1.09 ppm. The
breast muscles of fledgling golden eagles averaged 0.8 ppm.

These data indicate a generally low level of contamination,
but contamination varied throughout the areac Levels in prey
ranged from a high 0. 9 Ppm in the muscle of a Richardson's ground
sqxiirrel (Citellus rie'imrdsonli) to none in some of the muscle
semples taken from white-tailed jackrabbits (ig^JJ^ townsendii).
One red-tailed hawk egg contained over 12 ppm total organochlorine
insecticide residues while the breast muscle taken from a newly
hatched golden eagle contained 0.33 Ppm.

These background levels of contamination must be considered
when results of feeding trials in the present study are interpreted.
Undoubtedly they account for some of the variation observed in the
chemical analyses. However, I do not feel rhat background levels
were high enough to bias the conclusions of this study.

Table 3-> OrganocKLorine insecticide residues found in south- central
Montana^ I967

No. of Wet weight ppm (mean and range) Mean
speci- DDE DDD+ Dieldrin Heptachlor Total
mens DDT epoxide Residues

RODENTS AND lAGOMORPHS

Cottontail * 11
(Sylvilagus auduhonii
and S„ nuttallii )
White-tailed 1?
jackrahbit *
(lepus towsendii )
Richardson ground
squirrel * 10
(Citellus richardsonii)

Yellow-bellied marmot* 10
^Marmota flauiventris )

RAPTORS

Red-tailed hawks
(Btiteo jamacicensis)
Eggs

Newly-hatched young* 2

Fledglings
whole muscle

muscle (biopsy)

Golden eagle
(Aquila chrysaetos )

Newly-hatched young* 1
Fledglings

muscle 2

fat (biopsy)
Adult*

5
1

O0O2

O0O3
(0.02-

0.04)

0,02 O.OU 0.002 0
(0-0, 03 ) (0-0. 19) (0-0. 02 )

0.15
(0.03-

0.88)
0.02
(0. 02-
0.03)

O.OI+
(0.02-
0.06)

0.03
(0, 02-
O.OI4)

0.01
(0-0« 02)

5 2,90

0.32

0.35

0.37

(0, 2h-

(0,05-

(0.16-

(0. 09-

10.30)

1^33)

0.63)

0.80)

2 1.26

O.lU

0.12

0,02

(0.43-

(0. 09=

(0.05-

(0-0. Oi^)

2.10)

0.20)

O0I9)

0.93
(0. 61-

loi+l)

3ol7
(1.27-

6.87)

0. 30
(0,13-

0. 57)
0.16

O.J45
(0.20-
0„70)
3o67

181 §§)
0.04

0.07
(0.04-
0.10)

1«33
(o.4o-

2,30)

o.ou
(0, 02-
0.09)
0.15

0.31
(0.19-

0.44)

I089

(0.30r

0. 09

(0.02-
O0I6)
0.38

(0. 10-
l,4o)

0,18

(Oo 06-

0,38)

0,02

0,04
(O0O2-
O0O7)

.0,29

0. 07
(0.05-

0,08)

OolO^
0o45)
0,07

0
0

0.05
0.04

0.19
0.06

3»9i+

1,54

1,09

5.88

0. 59

0.33

0.80

5e85
0.21

*Muscle tissue

Source: Reynolds (in prep.)

Red-tailed Havk Feeding Trials
DDT accumulation in nestling havks

Throughout this discussion hawks which were fed DDT will be
referred to as experimental hawks and hawks which were not fed DDT
will be called controls » Controls were not fed DDT but obtained
organochlorine insecticide residues through natural foods.

Three experimental hawks and one control hawk were sacrificed
at the end of the nestling period. The DDT residues (DDE, DDD, DDT)
present in the tissue of these birds are compared in Table k.

Table k. Accumulation of DDT residues (DDT, DDD, DDE) in
nestling red-tailed hawks

Wet we

ight ppm (mean and range)

No.

Brain

Breast

muscle

Liver

DDD+

DDDf

birds Treatment

DDE

DDT DDE

DDT

DDE

DDT

1 Control

.I47 .61

.05

3 Fed DDT*

5.80

5.23 10.17

11.33

16. 30**

6,90

(3.22-

(3085- (9»70-

(9.IU-

7.60)

6,00) 10.60)

15.50)

* The dosage was 20 mg DDT/kg body wt every k days for
ho days.

^ One sample

-22-

It can be seen in Table k that DHT residues (based on ppan wet
weight) in experimental hawks were much higher than those in the
control bird. It is apparent that nestling hawks were unable to
completely metabolize or eliminate all the DDT which was fed and
consequently DDT residues acciamulated in their tissues. ,

Storage and loss of DDT by captive hawks

Six hawks which were fed DDT for kO days while in the nest were
kept in captivity for an additional hO days at which time they were
sacrificed. While in captivity three of the hawks were fed DDT at
the nestling rate and the remaining three were given food which
contained no DDT. One control was retained in captivity and was
sacrificed after 1+0 days.

The DDT residues in the tissues of the birds fed DDT for 80
days were much higher than those in the tissues from the control bird
(Table 5)» (The residue analyses are based on ppm wet weight; the
weight of captive hawks remained essentially the same from fledging
until they were sacrificed. )

At 80 days total residual DDT levels in the brains, livers, and
breast muscles of hawks fed DDT in captivity were about the same as
the levels in the biains, livers, and breast mtxscles of experimental
hawks sacrificed at the end of the nestling period.

Total DDT residues in the brains, breast muscles, and livers of
hawks fed DDT as nestlings but food devoid of DDT as captives were
only one-fourth as high as the residues found in experimental birds
sacrificed as nestlings (Table 6)= .■•

Table 5. Storage and loss of DDT residues (DDT, DDD, DDE)
in captive red-tailed hawks

Wet weight ppm

^mean <

ana. range j

No.

Brain

Breast

muscle

Liver

DDD+

birds

Treatment

DDE

DDT

DDE

DDT

DDE

DDT

Control

.16

.01+

.07

.01+

.12

.01+

Fed DDT*

5.57
(5.00-
6.lii)

3.30
(2. 59-
h.09)

16.1+7
(1I+.6O-
20.00)

10.72

(7.10-

17.80)

10.00#

I+.55

"Clean"
food**

2.38
(1.19-
U.25)

.38
(.29-

.1+6)

(1.19^'
8.60)

.63
(.30-

•91)

2.00#

.55

* Fed DDT during a 1+0-day nestling period and during a 1+0-day
post- fledgling period in captivity. The dosage was 20 mg
DDT/kg body wt every 1+ days for 80 days.

Fed DDT during a 1+0-day nestling period but were fed food
devoid of DDT during a UO-day post- fledgling period in
captivity.

# One sample

Table 6. Loss of DDT residues (DDT, DDD, DDE) by post-nestling,
captive red-tailed hawks on diets devoid of DDT

Total DDT residues (ppm wet weight) >

Tissues Nestlings Captives Change

Brain 11.03 2.76 75

Breast 21. 50 5-17 76

muscle

Liver 23.20 2.55 89

Note: Residues reported are means of three birds. Nestlings were
fed 20 mg DDT/kg body wt every 1+ days for 1+0 days. Captives
were fed DDT at the same rate as nestlings for 1+0 days but
were retained in captivity for hO additional days and fed
diets devoid of DDT.

-23-

In summary, the tissue analyses from experimental hawks indicate
that DDT residues did not accumulate in the breast muscle, liver, and
brain of captives but DDT residues accumulated in nestlings when fed
DDT at the same rate (Fig. 2). It is possible that the rapid growth
of the red- tailed hawk nestlings taxes their metabolic processes to
the extent that they are relatively inefficient in metabolizing and
eliminating DDT. However, once growth is essentially completed,
juvenile red-tailed hawks in captivity appear to have the ability
to metabolize and eliminate DDT at the employed dosages.

The basic differences between captive and wild juvenile red-
tailed hawks must be considered. Captive hawks acquired very little
exercise and were never short of food. The post-nest life of wild,
juvenile, red- tailed hawks is more demanding; the young bird must
learn to be an effective hunter, and when it acquires independence
from the parent, fend for itself. Thus, the ability of wild, post-
nestling juvenile hawks to handle loads of organochlorine insecti- ;
cides could be less than that exhibited by captive hawks of the same
age. More research is needed.

Changes in DDT metabolites '

In addition to the storage and loss of total DDT residues in
experimental hawks, a change in relative aimounts of each metabolite .
was observed. Recent studies have reported that conversion of DDT
to DDD occurs in animal tissue after death (Barker and Morrison,
196^+; Jefferies and Walker, 1966). I followed the procedure of
Stickel et al. (1966b) and added DDT and DDD residues together.

DDE and DDD+DDT are expressed as percentages of the total DDT

•

-25-

residues in Table 7» Data in Table 7 indicate that there are differ
ences in the relative amoimts of DDE in the different groups of
experimental hawks and in the different organs of hawks within each
group. Generally, the relative amounts of DDE are greater in ex-
perimental captive hawks than in experimental hawks which were sacri
ficed as nestlings. In captive hawks, total DDT residues (DDT, DDD,
DDE) decreased while relative amounts of DDE increased (Fig. 2).
This supports the contention by other workers (cf. Stickel et al. ,
1966b) that DDE is retained in the tissue longer than DDD or DDT.
DDT residues in hawk nestlings dying from "natural" causes

Information in the above section was derived from hawks which
were sacrificed for study according to a predetermined schedule,
but during the nestling period 6 red-tailed hawks died. Two hawk
nestlings from 1 nest were lost through great horned owl predation
and only fragmented remains were recovered. Post-mortem examina-
tions and chemical analyses are available for the remaining k nest-
lings.

All post-mortem examinations were conducted by veterinarians
of the Montana Livestock Sanitary Board. Pneumonia was listed by
the veterinarians as the cause of death of all nestlings. These
nestlings were recovered shortly after an extended period of wet,
cold weather. The adult male was present at each hawk eyrie where
nestlings were found dead but circumstantial evidence indicated
that the adult female at each nest was shot just prior to the period
of inclement weather.

In Table 8 the results of the analyses for DDT residues in the

-26-

Figure 2. Total DDT residues (DDT, DDD, DDE) in experimental
red- tailed hawks

-29-

brains of nestlings dying of pneumonia are compared with analyses
of brain tissue from hawks sacrificed at the end of the nestling
period. Total DDT residue levels (DDE, DDD, DDT) in the experi-
mental hawk nestling that died of pneumonia were almost 5 times
higher than those in the experimental nestlings which were sacri-
ficed. The relative amounts of DDT residues (DDE and DDD+DDT) in
the brains of hawks dying from pneumonia and hawks sacrificed at
the end of the nestling period are compared in Table 8. The ratio
of DDE to DDD+DDT was 1;1 in the brains of both experimental and
control hawks which were sacrificed according to a predetermined
schedule; a ratio of 1th was found in the brains of nestlings dying
of pneumonia.

Variations in experimental conditions and small sample size
make it difficult to interpret the observations which are outlined
above. Different ratios of the DDI metabolites in the brains of
nestling hawks indicate that more DOT residues accumulated in the
tissues of diseased nestlings than in the tissues of nestlings which
were sacrificed.

Growth and development

The nestling period in the life of an altricial bird is a
period which is characterized by high growth efficiency dependent
upon the ingestion of large qimntities of food (Kahl, I962). Gross
morphological changes occur in the young bird during a relatively
short time. It has been postulated that a raptor might be more sus-
ceptible to toxic chemicals dioring the nestling period than at any

-30-

The average nestliiig period for red-tailed hawks in south-
central Montana is Ul days. The gross morphological changes that
occur in red-tailed hawks from hatching to fledging are shown in
Plate 1.

Growth of birds in experimental and control groups was measured
to determine if any changes resulted from the induced DDT. The in-
dicies which were used to assess growth in nestlings included weight,
length of right foot pad, and plumage development <>

There were several sources of error in the growth data. Meas-
urements were taken from living birds under field conditions. The
grovrth analysis is based on the age of nestlings in days but only
in a few cases were ages known. When the age of a nestling was
unknown, it was established by comparing the nestling with known-age
individuals. The established ages are no more accurate than - one
day.

Body weight: The growth of experimental and control red-tailed
hawks is shown by changes in weight in Figures 3 and ko Three main
stages of nestling growth as shown by changes in weight can be rec-
ognized in altricial birds. There is (l) an initial period of slow
gain in weight, (s) a period of maximum increase in weight, and (3)
a final interval of minor fluctuations (Sumner, 1933). In red- tailed
hawks, the initial growth period lasts 5 days; the second period
lasts about 30 days; and the third period lasts approximately 6 days.
The growth curves of nestling, male red-tailed hawks reach the final
stage at a lower weight than females. The average maximum weights

•

-31-

Plate 1. Nestling red- tailed hawks: A, 1 and 2 days old;
B, 1+3 and h3 days old

-32-

Figure 3. Growth of male red- tailed hawk nestlings shown ■by-
changes in weight

OO^OQ.O o oo o
•0*0

o .8

• o*o

• o

0°

o.. J&?6o6?6»»66°*«*°**ft •

o 6 «
• o

o • 6

o" 6

o 6o„

^ • °
o •

O „ O '
o •

. §6 1° ^ ^ ^

' o

• o

' ' %. °'

. * go o

2/ . oControl

o .DDT

0 10 2 0 30 40

AGE IN DAYS

o Control
•DDT

• o

• • •

o o o

o o o • o

g o* • o<

30 ► • o" o'

o • • •

• 'Or.

8 o

to o

• o* o

• •

70 f • o

o •

• oo

10 I- o

• o •
• o

10 20 30 40

AGE IN DAYS

-33-

Figiire k. Growth of female red-tailed hawk nestlings shown by-
changes in weight

o o •

o Control

o o O
8 o o •
o . • o

• DDT

0 0 0 •

• • •

o o
o • o • o

o • o
006 • •

o •

o 00

o •

0 0 0

o •

o* o

AGE IN DAYS

of control and experimental hawks were not significantly differento
Male control and experimental hawks weighed 33 oz (935 g) and 3^ oz
(96^+ g) respectively and females weighed kl oz (II62 g) ajid 4^1 oz
{l2kl g) respectively. Control, nestling, male and female red-
tailed hawks achieved more than ^l and 102^ respectively of their
adult weights.

Weights of nestling hawks v8,ry a great deal but Figures 3 and
h show that the DDT dosage which was used in these triaJLs did not
affect the growth of experimental nestlings as shown hy changes in
weight.

Foot pad lengths The increase in length of the right foot pad
(from the tip of the hallux to the tip of the middle toe) of red-
tailed hawks is shown in Figure 5<. The foot pad grows rapidly from
hatching until about day 25 and at fledging the growth of the pad
is essentially complete. Sexual dimorphism in the length of the
foot pad in red-tailed hawks appeared between day 10 and I5. The
foot of the female grows at a faster rate than that of the male
until day 25. The mean foot pad length at fledging in known sex
birds (both experimental and control) is 3o31 in. (3»25 - 3-^5) in
males and 3.6^+ in. (3.62 - 3-69) in females.

The growth of the foot pad of experimental birds was not dif-
ferent from that of control birds.

Development of the feather coat: The development of the feather
coat of nestling hawks was studied in two ways : l) the appearance
of contour feathers in the varioxis pterylae was recorded and 2) the
seventh right primary and the sixth right rectrix were measured.

•

-35-

Figure 5« Growth of the right foot pad (from the tip of the
hallux to the tip of the middle toe ) : A, female,
nestling golden eagles; B, female, nestling red-
tailed hawks; and C, male, nestling red- tailed
hawks

-36-

The developnent of the Juvenal plumage and other main points in the
physical development of red-tailed hawks is shown in Table 9» The
nomenclature follows that of Conrpton (l938) and Humphrey and Parks
(1959).

Because observations on the appearance of the Juvenal plum-
age in the various feather tracts were made at k-d&y intervals, it
was necessary to arrange the data in a general form. No differ-
ences in the development of Juvenal plumage of control and experi-
mental hawks were detected.

The growth of the seventh right primary and the sixth right
rectrix in both experimental and control nestlings is shown in Fig-
ures 6-9» These flight feathers were measured from their tips to
the points where the shafts emerged from the skin. Quills of flight
feathers are the first to appear and these feathers are still in a
state of rapid growth at fledging. The seventh right primary ach-
ieves approximately three- foixrths its total length and the sixth
right rectrix achieves two-thirds its total length at fledging.

There is a great deal of individual variation between birds
in the growth of the primary and rectrix but there were apparently
no significant differences between control and experimental birds.
Behavior

Warner et aJL. (1966) pointed out that the behavior of any organ-
ism represents the integrated result of a diversity of biochemical
and physical processes. Moreover, "Behavior patterns are known to
be highly sensitive to change in the steady state of an organism.
This sensitivity is one of the key values for their use in exploring

Table 9- The development of the juvenal plumage and other main points
in the physical development of red- tailed hawks and golden
eagles.

Age in Days ;

Tract 0-7 8-li^ 15-21 22-28 29-35 36-^^2 43-49 50-56 80

Red- tailed hawk

Alar tract
Primaries
Secondaries
Caudal tract
Rectrices
Humeral tract
Spinal tract
Ventral tract
Capital tract
Crural tract
Femoral tract

Eye color Brown Gray Yellow

Ear opening V NV NV

Egg tooth Pres. Ahs. Abs.

Toe nails Pink-
Black

Golden eagle

Alar tract

Primaries S U

Secondaries S U

Caudal tract

Rectrices S U

Hxmieral tract S U

Spinal tract S
Ventral tract S
Capital tract S U U

Crural tract
Femoral tract

Ear openings V NV

Egg tooth Pres. Ahs. Abs. Abs, Abs.

Toe nails Pink Black

Notes: S indicates feather tips breaking the skin;

U feather tips breaking their sheaths;

V ear openings are visable;

NV ear openings are obscured by bristles

-37-

■

•

-38-

Figure 6. The length of the seventh right primaxy of nestling,
male red- tailed hawks

oControl
• DDT

• o

111 '

- 6
Z

• o

o
o

.0 o

o«

»o

0»

20 30
AGE IN DAYS

•

-39-

Figure 7. The length of the seventh right primary of nestling,
female red-tailed hawks

oControl

DDT

o o,

o •

o .
o o . .

8°.:

o9 • •

Q 9o

O A • •

got 6*

20 30
AGE IN DAYS

-ko-

Figure 8. The length of the sixth right rectrix of nestling,
male red-tailed hawks

o Contro I
• DDT

•••

o
o

o •

• o

o •

20 30
AGE IN DAYS

•

-kl-

Figure 9« The length of the sixth right rectrix of nestling,
female red-tailed hawks

.1^2-

sublethal toxication (Warner et al., I966: 22i+-225)o"

Quantitative measurements of behavior patterns were not under-
taken during this inquiry; however, casual observations were made.
Seven red- tailed hawk nestlings were taken into captivity at the
end of the nestling period; 6 of the hawks were on DDT diets and
1 hawk acted as a control during the nestling periodo All hawks
which were taken into captivity were handled similarly.

One captive hawk that had been on a DDT diet during the nest-
ling period never learned to feed itself when food was placed on its
perch and food had to be lifted to its beak before it woiild eat«
All other captive hawks readily learned to feed themselves, Organo-
chlorine insecticide residues in the tissue of the hawk which
failed to learn to eat were no higher than those which were foxmd
in other hawks under similar experimental conditions. Ludwig (1965)
and Warner et al« (1966) found that sublethal levels of both organo-
phosphorus and organochlorine insecticides affect the learning abil-
ity of fish. However, the effect of sublethal residues of organo-
chlorine insecticides on the learning ability of birds has not been
measured under controlled conditions.

Golden Eagle Feeding Trials
DDT accumulation in nestling eaglets

The DDT residues (DDT, DDD, DDE) found in nestling golden
eagles and red- tailed hawks sacrificed at the end of the nestling
period are compared in Table 10, DDT residues found in the control
eaglet were lower than those found in the control red-tailed hawk.

.1,3-

Residues in experimental hawks and eagle were much higher than those
fo\jnd in the control birds. Differences among the amounts of DDT
residues stores in the various tissues of experimental birds are
apparent. However, the residual levels in experimental birds of
both species are of the same general magnitude. This indicates that
nestling eagles are similar to nestling hawks in their inability to
completely metabolize and eliminate all the DDT which was fed and
consequently DDT residues accumulate in their tissue.
Growth and development

Nestling golden eagles were handled similarly to nestling
hawks and the same sources of error are present in the growth data
obtained from eagles.

The average nestling period for golden eagles is 75 days
(Reynolds, in prep. ) as compared to the iH-day nestling period of
the red-tailed hawk. The gross morphological changes that occur
from hatching to fledging are shown in Plate 2,

Body weight : All the eaglets used in this experiment were
females. Changes in weight of both experimental and control eaglets
are shown in Figure 10« The initial growth period which is char-
acterized by slow gains in weight lasts about 10 days; the period
of maximum increase in weight extends over 55 days; the third inter-
val of minor fluctuations in weight lasts about 10 days. The aver-
age maximum weight of control and experimental female nestling
golden eagles was lh7 oz (i+l66 g) and 150 oz (I+25I g) respectively.
Female nestling golden eagles achieve about ITfo of their adult
weight.

•

Table 10. DDT residues (DDE, DDD, DDT) in control and experimental golden eagles and red-tailed
hawks at the end of the nestling period

Species

No.
of

birds Treatment

Wet weight ppm
Brain

Breast muscle

DDE

DDD+
DDT

DDE

DDD+
DDT

Liver

DDE

DDD-t-
DDT

Golden
eagle

Red-tailed
hawk

Control

.15

,49

.04

.47

.20

.61

.19

.05

.19

.13

Golden
eagle

Red-tailed
hawk

Fed DDT*

2.84

5.80

3.80

9ol2

5.23 16.30

22.97 11»90

6.92

10.17

12o22

11.33

* The dosage was 20 mg DDT/kg body wt every 4 days

Plate 2. Nestling golden eagles: A, 9 and 12 days old
B, 69 and 72 days old

•

-h6-

The weights of nestling eagles vary a great deal but the data
in Figure 10 show that the DDT dosage which was used in these trials
did not affect the growth of the experimental nestling as shown hy
changes in weight.

Foot pad length; The increase in the length of the right foot
pad of golden eagle nestlings is shown in Figure 5» The foot pad
grows rapidly from hatching until about day 55" At fledging the
growth of the foot pad is essentially coniplete. The average length
of the foot pad at fledging was 5.8? in. (5.75-6.00) in the female
eagles used in this study.

From the data shown in Figure 3, it does not appear that the
growth of the foot pad of the eaglet which was experimentally fed
DDT was different than that of control birds.

Development of the feather coat : Quills of flight feathers
began to appear during the third week in golden eagles. At fledg-
ing all flight feathers were well along in development and the
majority of the contour feathers were \msheathing in all pterylae
(Table 8).

There were some discrepancies between the plumage data which I
collected and that which were gathered by Sumner (1933 ) for the
golden eagle. Sumner (1933; 281-282) reported that in a male golden
eagle the quill of the sixth primary appeared at day 7 and the sixth
left rectrix appeared at day 9. I did not observe quills appearing
in the caudal or alar tracts \intil the third week (between days 15-
21).

The growth of the seventh right primary and the sixth right

-hi

Figure 10. Growth of female golden eagle nestlings shown
by changes in weight

140

120

100

1 80
O

- 60

• *

20 ^ o Contro I

o . DDT

o
o o

10 20 30 40 50 60 70 80

AGE IN DAYS

-1+8- . ' -

reetrix in both experimental and control eaglets is shown in Fig-
ures 11 and 12. There is a great deal of individual variation in
the growth of these feathers hut there were apparently no differ-
ences between the control eaglets and the eaglet fed DDT.

General Disctission
The observations outlined in this section are sumtnarized below:

1. Low levels of DDT and its metabolites (DDD and DDE),
dieldrin and in some instances heptachlor epoxide were
found in the tissue of control red-tailed hawks and golden
eagles. The presence of these residues indicated that
organochlorine insecticide residues were being trans-
ferred through the natxiral food.

2. At the dosage used in the feeding trials (20 mg DDT/kg
body wt every h days), DDT and its metabolites accumulated
in the brains, breast muscles, and livers of nestling red-
tailed hawks and golden eagles. ■ " ' \

3. Residual levels of DDT and its metabolites were similar
in the brains, livers, and breast muscles of hawks fed DDT
as nestlings and hawks fed DDT as nestlings and for a kO~
day post-nestling period.

4. Total DDT residues in the brains, breast muscles, and
livers of hawks fed DDT as nestlings and food devoid of
DDT for a kO~d.B.y post-nestling period were only one-foiarth
as high as the residuesfound in the same tissue taken from
hawks fed DDT during the nestling period.

Figure 11. The length of the seventh right primary of nestling,
female golden eagles

"Control
• DDT

10 20 30 40 50 60 70 80
AGE IN DAYS

-50-

Figxire 12. The length of the sixth right rectrix of nestling
female golden eagles

14 .

5 «

Z 7

I—
O

•Control
• DDT

10 20 30 40 50
AGE IN DAYS

60 70

5o The data suggest that more DDT residues accumulated in
the brains, breast muscles, and livers of diseased nestlings
than in the brains, breast muscles, and livers of healthy-
nestlings o

6. DDE is retained in the tissue of juvenile red-tailed
hawks longer than DDIHDDT. . .

7. One of six fledgling red- tailed hawks which were fed

DDT during the nestling period failed to learn to feed itself
dxiring a Uo-day post-fledging period in captivity.

8. DDT at the dosage used in these trials did not affect
the growth of red- tailed hawks and golden eagles.

Even though nestling hawks and eagles accumulated substantial
levels of DDT in vital body organs (brain and liver), these levels
had no measurable affect on growth. These results gave no insight
into other possible effects of the induced DDT on the nestlings.
Burlington and Lindman (1950 ) found that the growth of white leg-
horn cockerels was not affected by subletlB.1 injections of DDT but
the development of the comb, wattles, and testes was inhibited as
a result of the treatment. Warner et al. (1966; 2k^) stated that
"Empirical research and experience are teaching us^ sometimes the
hard way, the folly of assuming that lack of evidence is the same
as negative evidence. " Iftifortunately, our present knowledge per-
mits only an imperfect estimate of the effects of organochlorine
accumulation on any species.

/' r . ■ SUMMARY _ ,

1. An investigation was conducted during the spring and simmer
of 1967 in south-central Montana to obtain informtion on the re-
sponse of juvenile red- tailed hawks and golden eagles to DDT in the
diet. The experiments were designed to; l) measure the accumula-
tion of DDT residues in nestling hawks and eagles, 2) measure storage
and loss of DDT residues in post-nestling hawks and eagles, and 3)
determine the effects of feeding DDT on their growth, development,
and hehavioro

2. Low levels of DDT and its metabolites (DDD and DDE), ,
dieldrin, and in some instances heptachlor epoxide were found in
the tissue of control red- tailed hawks and golden eagles. The pres-
ence of these residues indicated that organochlorine insecticide
residues were being transferred through the natural food.

3. At the dosage used in the feeding trials (20 mg DDT/kg
body wt every k days), DDT and its metabolites accumxilated in the
brains, breast muscles, and livers of nestling red-tailed hawks and
golden eagles.

k. Residual levels of DDT and its metabolites were similar in
the brains, livers, and breast muscles of hawks fed DDT as nestlings
and hawks fed DDT as nestlings and for a UO-day post-nestling period.

5. Total DDT residues (DDT, DDD, DDE) in the brains, breast
muscles, and livers of hawks fed DDT as nestlings but food devoid of
DDT for a i;0-day post-nestling period were only one-fourth as high
as the residues found in the same tissue taken from hawks fed DDT dur-
ing the nestlirig period. . . . ' * " '• . ' , • ' .

- -53- . .:

6. The data suggest that more DDT residues accumulated in the
"brains, breast muscles, and livers of diseased nestlings than in the
brains, breast muscles, and livers of healthy nest lings. • -., <

7. DDE is retained in the tissue of juvenile red-tailed hawks
longer than DDD+DDT.

8. One of six red- tailed hawks which were fed DDT during the
nestling period failed to learn to feed itself during a UO-day post-
fledging period in captivity,

9. DDT at the dosage used in these trials did not affect the
growth of red- tailed hawks and golden eagles. . .

LrrERATTJRE CITED

Ames, Po Lo 19660 DDT residues in the eggs of the osprey in the
northeastern IMited States and their relation to nesting
success. J. Applo Ecolo 3(Supplo); 87-97o

and Go S. Mersereauo 1964. Some factors in the de-
cline of the osprey in Connecticuto Auk 8I: 173-185.

Barker, P. S,, and F. 0. Morrison, 196^+0 Breakdown of DDT to
DDD in the mouse. Can. J, Zool, 42: 32U-325.

Burlington, H. and V. F. Linderaan. 1950, Effects of DDT on
testes and secondary sex characters of white leghorn
cockerels, Proc, Soc, Exptl. Biol, 74:48-51.

Cade, To J., C. M. White, and J, R. Hough, 1968, Peregrines and
pesticides in Alaskao Condor 70:170-178.

Compton, L, V, 1938, The pterylosis of the falconiformes with
special attention to the taxonomic position of the osprey.
Ifiiiv, Calif, Publ, Zool, 42: 173-212.

Cottam, Co, D, A, Munro, R, H, Pough, H, R, Hockbaum, R. A.

McCabe, and I, N, Gabrielson, 1961. Report to the American
Ornithologists' Union by the Committee on Bird Protection.
Auk 79: 463-4780

Craighead, J. J,, and F, C. Craighead, Jr. 1956. Hawks, owls,
and wildlife, Stackpole Co,, Harrisburg, Penn. and Wildl.
^^gmt. Inst., Washington, D, C. 443 P»

Cramp, S„ 1963, Toxic chemicals and birds of prey. British Birds
56: 124-139.

Durham, W. F, , P. Ortega, and W. J. Hayes, Jr, 1963- The effects
of various dietary levels of DDT on liver function, cell
morphology, and DDT storage in the rhesus monkey. Arch, Int.
Pharocodyh, ihlt III-I29,

Dustman, E. H. 1966, Monitoring wildlife for pesticide contents.
In Scientific aspects of pest control. National Academy of
Sciences, National Research Council, Washington, D, C.

Enderson, J. H. and D. D. Berger, I968. Chlorinated hydrocarbons
in peregrines and their prey species from northern Canada.
Condor 70: l49-153o

-54-

-55-

Gandal, Co Po 1956, Satisfactory general anesthesia in birds.
Jo Am, Veto Medo Assoco 1938 s 332-335<.

Hall, Eo Ro and Ko Ro Kelsono 1959» The mammals of North America.
Ronald Press Coo, New York, N. Yo 2 v IO83 p.

Hickey, Jo J. 1966. Birds and pesticides, p. 3l8-329o In A.

Stefferud (edo )o Birds in our lives. Uo S. Fish and Wildl.
Ser., Washington, D. C.

(edo )o In press. Peregrine ftilcon populations; their
biology and decline. Univ<, Wisconsin Press, Madison.

Hofftnann, R. S., and D. L. Pattie. 1963. A guide to Montana

mammals; identification, habitat, distribution, and abundance.
Associated Students of University of Montana Store, Missoula.

133 Po

Humphrey, P. S., and K, Parks. 1959° An approach to the study of
molts and plumages. Auk 76: I-3I0

Jefferies, D. J. and C. H. Wa3ker. I9660 Uptake of p,p'-DDT and
its postmortem breakdown in the avian liver. Nature 212:

533-53^-

Kahl, M, P., Jr. I962. Bioenergetics of growth in nestling wood
storks. Condor 64: 169-I83

Koeman, J. H. , and H. van Genderen. I966. Some preliminary notes
on residues of chlorinated hydrocarbons in birds and mammals
in the Netherlands. J. Appl. Ecol. (Suppl. ) 3°- 26I-269.

Lockie, J. D., and D. A, Ratcliffe. 196^+. Insecticides and
Scottish golden eagles. British Birds 57? 89-101.

Ludwig, Ho Fo 1965. Toxicant- induced behavioral and histological
pathology: a quantitative study of sublethal toxication in
the acquatic environment. Final report. Engineering Science
Inco (origo not seeno Iji N. W. Moore. 1967« )

Lumb, W. Vo 1963 Small animal anesthesia. Lea and Febiger,
Philadelphia, Penn. ^4-20 p.

McGteihan, J. 1966. Ecology of the golden eagle. Unpub. M.A, Thesis,
Univ. of Montana, Missoulao 78 po

o 1967. Quantified estimates of predation by a golden
eagle population. J. Wildlo Mgmt. 31: 1+69;471»

o 19680 Ecology of the golden eagle. Auk 85: 1-12.

-56-

Menzie, Co M„ 19660 Metabolism of pesticideso U- S, Fish and
Wildl, Sero SpeCo Sci, Rept. sWildlo l+3» 27^ p.

Metcalf, R« L,. 1955o Organic insecticides, their chemistry and
mode of actiono Interscience Publishers, New York, N. Y.

392 Po (origo not seeno la Menzie. 1966)0

Moore, No Wo 1965- Pesticides and birds --a review of the situa-
tion in Great Britain in 1965" Bird Study 12: 222-252.

1967° A synopsis of the pesticide problem, p. 75-129-

In Jo Bo Cragg (edo ) Advances in ecological research.
Academic Press. New York, No Yo

Prestt, lo 19650 An enquiry into the recent breeding success of
some of the smll birds of prey and crows in Britain. Bird
Study 12s 169-22I0

. 19660 Studies of recent changes in the status of
some birds of prey and fish-beating birds in Britain. J. Appl.
Ecolo 3 (Supplo ) 107-112o

Radeleff, R. D. 1950. Omentectomy of cattle for studying insecti-
cide residue in the body. Vet. Med. h^'' 125-128.

Ratcliffe, D. A. 1963. The status of the peregrine in Great
Britain. Bird Study 10; 56-9O.

. 1965» The peregrine situation in Great Britain in
1963-6i|. Bird Study 12; 66-82.

Reynolds, H. V. , III. In prep. Ecology of the golden eagle in
south-central Montana. M. S, Thesis. Univ. of Montana,
Missoula.

Richmond, C. W. , and F. H. Knowlton. I89I+. Birds of south-central
Montanao Auk 11: 298-308.

Rudd, Ro Lo 196^0 Pesticides and the living landscapeo Univ.
Wisconsin Press, Madison. 320 p.

Sanger, Vo L. and H. R. Smith. 1957. A general anesthesia in
birds. J. Am. Vet. Med. Assoc. I3I; 52-55«

Saunders, A. A. 192I. A distributional list of the birds of Montana,
Pacific Coast Avif. ik: 1-lkk,

Schmid, Fo C. 1966. The status of the osprey in Cape May County,
New Jersey between 1939 and 1963» Chesapeake Science

7; 220-223.

-57-

Shearer, Ho K. (edo )» 1958. The Montana almanac. Montana State
Iftiiversity Press, Missoula. 469 P-

Sprunt, Ao, IV and F„ J. Ligas. 1966. Audubon bald eagle studies,
I96O-I9660 Proc. 62nd Conv. Natl. Audubon Soc, Sacramento,
Calif. Unnumbered pp. Reprint.

Stickel, Lo F. , N. J. Chura, P. A. Stewart, C. M. Menzie, R. M.
Prouty, and W„ L. Reichel. 1966ao Bald eagle pesticide re-
lations. Trans. N. Am. Wildl. Conf, 31 2 190-200,

, W. H. Stickel, and R. Christensen. 1966b. Resi-
dues of DDT in brains and bodies of birds that died on dosage
and in survivors. Science 151: 1549-15510

Stickel, W. H., W. E. Dodge, W. G. Sheldon, J. B. DeWitt, and L. F.
Stickel. 1965. Body condition and response to pesticides in
woodcocks. Jo Wildl. Mgmt. 29: lU7-155o

Sumner, E. L. , Jr. 1933° Growth in some young raptorial birds.
Univ. Calif. Publ. Zool, kOt 277-307.

U. S. Department of Commerce, Bureau of the Census. I966. 196^+
United States census of agricultures Park County, Montana.
Series AC 6i|-Pl. 6 p.

U. S. Department of Commerce, Weather Bvireau. 1967. Climatological
datas Montana. 70 (2-8_: 2I-I85.

Warmer, R. E. , K. K. Peterson, L. Borgman. I9660 Behavioxjral patho-
logy in fish: a quantitative study of sublethal pesticide
toxication. J. Appl. Ecol. 3(6uppl. ): 7I-85.

Woodwell, G. M. 1967. Toxic substances and ecological cycles.
Scientific American 2l6 (3):2l4-31.

VinBter, C. F. , Jr. and D. B. Wingate. I968. DDT residues and
declining reproduction in the Bermuda petrel. Science 159s
979-981.

APPENDIX A
THE BIOPSIC PROCEDURE

THE BIOPSIC PROCEDURE
The Biopsy

Biopsies have been utilized in collecting tissue for the study
of insecticide kenetics in monkeys (Durham, et al, , 1963) and cattle
(Radeleff, 1950). Enderson (1968) used biopsies to collect adipose
tissue from ad\ilt peregrine falcons captured in the Arctic. A
biopsic technique for collecting tissue from raptors vras used in
this study for two reasons : first, it enabled the investigator to
sample the persistant pesticide residue level present in various
raptor species on a study area without sacrificing birds and, thus,
altering the composition of the populations under observation; and
second, the technique increased the sunount of data that could be ob-
tained from the limited number of raptors used in the DDT trials.

Procedure

After experimenting with magpies (Pica pica) and captive rap-
tors, a method of taking small samples of muscle from a bird's pec-
toralis miscle was developed. During the initial experiments, I
found it was possible to carry out the biopsy without first anesthet-
izing nestling hawks and eagles, and they seemingly experienced little
paino Once a bird was sufficiently developed to leave the nest, an
anesthesia was necessaryo The recommended anesthetic, dosage, and
anesthetizing procedure for older birds is outlined below.

To collect a small sample of muscle the raptor is anesthetized
or in the case of a nestling firmly restrained. A large cloth is
placed over the nestling's head and the wings are folded aginst the

-59-

-60-

body. After the wings are secure, the legs are held and the feet
fitted into a smll leather sack. A young raptor's talons can in-
flict serious wounds if the handler is unwaryo Once the talons are
rendered useless, the bird is placed on its back. The cloth should
remain over the nestling's head as it helps to keep it calm.

In preparing for surgery, the feathers of the keel region are
wetted with alcohol from a small squeeze bottle. The feathers are
then spread to expose the median apterium. The exposed skin is
cleaned with a small disposable alcohol sponge. With a sharp scal-
pel a 25 mm anterion-posterior incision is made in the skin to one
side of the keel ridge Just posterior to the apex. A second incis-
ion k mm deep and 20 mm long is made in the pectoralis muscle. The
mxiscle tissue at the anterior end of the incision is grasped with
pointed forceps. A third incision of the same length is made in
the muscle parallel to the first. This second incision is angled
so that a small triangular strip of muscle can be removed. This
procedvire is illustrated in Figure 17- The length and depth of the
incision must be adapted to the size of the bird. The measure-
ments given here are for a juvenile golden eagle.

The average weight of tissue samples taken from red-tailed
hawks was .05 g, and ,3 g was the average weight of samples taken
from golden eagles.

After the tissue sample is obtained, it is inserted into a clean
vial and frozen.

The wound is not sutrrred, but left open to drain. It is, how-
ever, sprayed with an aerosol topical calloidin dressing. During

-61-

Figure 13. The biopsy: l) the site where the biopsy is

performed; 2) the initial incision in the skin;
3) the first incision in the pectoralis muscle;
h) and 5) a small triangular strip of muscle
is removed for residue analysis

-62-

experimental tests imsutured wounds healed faster and with less in-
fection than birds with sutured wounds. Conrplete healing requires
about ten days. When called, manned experimental hawks would readily
fly to the gloved fist the next day.

If bleeding occurs, it can be stopped by placing a small dis-
posable alcohol sponge on the wound and applying fingertip pressure
for a few minutes.

No adipose tissue that can readily be taken, using this tech-
nique, was found on nestling red- tailed hawks, Swainson's hawks, or
marsh hawks. Adipose tissue can be obtained from subcutaneous de-
posits in nestling golden eagles; however, the incision must be made
near the posterior end of the keel. Samples of adipose tissue from
subcutaneous deposits can be obtained from older red-tailed hawks
if they are in good condition. These fat samples can be taken with-
out cutting into the pectoralis muscle.

Results and discussion

During the development of the technique, more than 50 small
samples of muscle were collected from four raptor species : golden
eagle, red- tailed hawk, Swainson's hawk, and marsh hawk. Biopsies
were repeated at various intervals on some individuals and a series
of tissue samples was obtained. In all cases the wounds healed with-
out complication.

No sample can represent in every respect the whole from which
it is drawn and it was necessary to determine discrepancies in water
content, liquid content, and organochlorine insecticide content that
exist between the entire breast muscle and the small sample of muscle

-63-

takeiio Chemical analysis data from breast muscle biopsies and
entire breast muscles which were taken from fledgling red-tailed
hawks fed DDT as nestlings at the rate of 20 mg DDT/kg body wt
every k days are compared in Table 11.

Table llo Water, lipid and organo chlorine insecticide con-
tents in whole pectoralis muscles and small
muscle samples (biopsies) which were taken from
pectoralis muscles of fledgling red-tailed hawks

Mean and

range

Noe of

Wet weight (ppm)

Tissue

speci-

DDD+

collections

mens

water

lipid

DDE

DDT

Whole

72o00

1. 09

IO0I7

11. 33

muscle

(70,30-

(.65-

(9o 70-

(9.li^-

73ol2)

1.65)

10.60)

15.1+0)

Biopsy

7k,kl

9.19

8.55

(7I0 h2-

(1.13-

{1.0k-

(6«3i+-

77=73)

8,16)

lU.OO)

ll.i+5)

Note: All birds were fed 20 mg DDT/kg body wt every h
days for kO days during the nestling period

The water content was higher in muscle samples than in whole
muscles and on the average, samples contained more than twice the
extractable lipids found in whole muscles. The mean total DDT con-
tent (wet weight basis) in biopsies is 31^ below the mean amoimts
found in the whole muscle. However, the relative amount of DDT
metabolites (DDT+DDD and DDE) are nearly the same in both groups.

In sximmary, the chlorinated hydrocarbon residues determined
from muscle samples, which were taken via the biopsy, should be
viewed as estimates of the contents of the entire tissue rather

than as measures of the residues present in the whole muscle. Appar-
ently, there is a variation in the storage of insecticide residues
in different parts of the muscle. This warrants further investiga-
tion.

. ' - "ft ■

The Anesthetic

Many of the anesthetic agents commonly used for small mammals
have heen unsatisfactory for anesthetizing various avian species.
Gandal (1956) found Equi-thesin l/ to be a suitable general anesthet-
ic for birds. Each 500 cc of Equi-thesin contains 21.1 g chloral
hydrate, ^.8 g pentobarbital, and 10.6 g magnesium sulfate in an
aqueous solution of propylene glycol with 9. 3% alcohol. The manu-
facturer's literature states: "The combination of chloral hydrate,
magnesium sulfate and pentobarbital provides some of the desirable
depressant action of each compound without the pronounced toxicities
of any drug, " The literature further reports : "One of the most
important advantages of this combination is the absence of the ex-
citement stage. This is accomplished with the small amount of magnes-
Ivm sulfate, measured so that toxic effects and the narrow margin of
safety characterized by larger doses do not appear. "

Procedure

Because of the difficulties in attaining vein puncture, Gandal
(1956) recommended the intramuscular route (via the breast muscle)
of drxog administration. Sanger and Smith (1957) reported some local

1/ Equi-thesin is a product of Jensen-Salsbery Laboratories.

-65-

inflananation in the muscle after Equi-thesin was injected in their
experimental hirds^ Instead, I followed Lumb's (1963: 277) recom-
mendation and injected the drug into the leg muscle to eliminate
the effects of inflammation upon the bird's flight.

After preliminary experiments, the basic procedure in this
study was to weigh each bird with a spring scale or beam balance,
compute a dose, inject the prescribed amount into the leg muscle,
release the bird on the floor in a quiet roomo The bird was periodi-
cally checked to determine its reactions to the drug» One cc, dis-
posable, plastic, tuberculin syringes with 25-gage needles were used
for administering the drug to smaller raptors; correspondingly
larger needles and syringes were used for larger raptors.

Results and discussion

Before anesthetizing raptors, I tested Equi-thesin at different
dosages on a group of captive magpies. I successfully anesthetized
5 magpies in 5 trials using Gandal's (1956) recommended dosage. Four
other attempts with higher doses than recoimnended resulted in three
birds being successfully anesthetized. The fourth bird died when
more than twice the recommended dose was given. These trials are
outlined in Table 12.

Three raptors (two red-tailed hawks and one sharp- shinned hawk)
died when Equi-thesin was administered at the rates recommended by
Gandal and others for birds. Therefore, I found it necessary to
establish a correct dose for falconiform birds. To establish the
correct dose, I administered Equi-thesin to a series of raptors; I

beib

d —

OSSX

h,l

OSSi

O.S

84 .8

S4SI

f>slb

00 .R

ooox

oe.s

0?XX

£<3Xb

4s .S

0,1

84.0

iwarf jfaoJil

Td.O

S&4

Jviui ifruM

ev.o

■ "

£^ .1

eT.o

•ex

0^.0

ex?

4sde

»X, ^^5

05 . 1

0£.d

oos4

»X8a»

ofi

0?.I

00.?

0S4£

0^,1

od.?

acre

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04 .y

bail)

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oesf

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-68-

started with relatively low levels and continued until I found a
satisfactory dosage. No mviltiple doses were given. A total of hS
experimental injections were administered to 21 individual raptors
representing seven species: 1 prairie falcon, 1 sparrow hawk, 1
sharp-shinned hawk, 1 marsh hawk, 2 Swainson's hawks, 7 red- tailed
hawks, and 8 golden eagles. Three other raptors (l golden eagle
and 2 red- tailed hawks) were sacrificed with overdoses of the drug.
These data are presented in Table 12,

On the basis of these tests, minimum doses that would consis-
tently produce surgical anesthesia (L\anb, 1963:10) were determined
for four species: prairie falcon, red- tailed hawk, Swainson's hawk,
and marsh hawko An insufficient number of trials were run to estab-
lish the correct dose for sparrow hawks or sharp-shinned hawks. Suc-
cessful anesthesia was obtained with golden eagles but results were
so variable that no conclusions could be made (Table 13).

A wide variation in reaction to the drug has been observed in
nestling golden eagles and golden eagles that have been retained in
captivity for some time. Surgical anesthesia and satisfactory recov-
ery were achieved in nestling golden eagles with doses ranging from
2.0 - 2,5 cc/kg body weight, A dose of l.k3 cc/kg body weight ach-
ieved surgical anesthesia in two captive golden eagles 1, 5 years old
or older. The duration of the anesthesia was more than 3 hours for
the first and the second eagle was revived from the anesthesia (after
2k hours ) when a 1, 5 cc dose of Mikedimide 2/ (a barbiturate antagon-
ist) was administered. Older wild eagles have not been anesthetized

2/ Mikedimide is a product of the Paralem Corporation

-69-

Table 13o Dosage of Equi-thesin for some avian species

Species

Age

No. of
birds

Dosage
(cc/kg
body wt)

Mean

Induction
time

(minutes )

Duration*
(minutes )

Magpie

2o5

Prairie falcon

1.5

Swainson's hawk

1.6

192

Red-tailed hawk

1.5

322

Marsh hawk

1. 53

270

Golden eagle

1.9

Golden eagle**

I2 yr-

+ 2

1,U5

360+

* Interval between light anesthesia and regaining the ability
to lift the head

** Not recommended - see text

-70-

for comparison.

Jxi addition to the three raptors which died during the initial
experiments and the three which died from deliberate overdoses of
drug, one juvenile red- tailed hawk, 82 days old, died unexpectedly
when the drug was administered at a rate of 1,6 cc/kg body weight.

Although successful anesthesia was achieved 2k times in 5
raptor species, the unexpected death of the juvenile red-tailed
hawk and the extended duration of anesthesia in one golden eagle
renders Equi-thesin unsatisfactory for valuable experimental and
trained birds of prey except in case of emergency.

APEEMDIX B
AMLYTIGAL METHODOLOGY

AMLYTIGAL METHODOLOGY

All chemical determinations reported in this study were made hy
the Wisconsin Alumni Research Foundation. The following description
of procediures was provided hy the Chemical Department (in litt. ).

"Sample preparation:

"Total weights are originally taken on all samples. The samples
are then weighed into tared beakers. If the total weight is less
than 20 gm the entire sample is used. If the total weight is greater
than 20 gm the sample is homogenized and a 20 gm portion taken for
analysis. The beakers and samples are dried in an air oven at UO-
^5° C for 36-48 hours o The beakers are weighed and the percent
moisture determined.

"The samples are then ground with sodium sulfate and transferred
to extraction thimbles. The thimbles are placed in the Soxhlet ap-
paratus and extracted with a mixture of 70 ml ethyl ether and
170 pet. ether for 8 hours. After extraction the ethers are re-
moved from the erlenmyer flasks by evaporation on a steam bath. The
fat is dissolved in pet. ether and transferred to a volumetric flask.
After making to volume, one half of the solution is pipetted into a
tared beaker. The solvent is removed on a steam bath and the beaker
dried in an air oven at kO-k^ °C for three hours. The beaker is re-
weighed and the percent of fat calculated.

"The remaining solvent in the volumetric flask is washed onto
a florisil column. Pesticides are eluted from the colxomn with 5^-95^
(ethyl ether-pet. ether) and 15^-85^ (ethyl ether - pet. ether) solu-
tions. The respective solutions are taken to near dryness on a steam

-72-

9^-

-1 r.i

-73-

bath and then transferred to a volumetric flask. After making to
volume, a known volume of each is injected into the gas chromata-
graph.

"Instrumental Conditions

"Barber- Colman Pesticide Analyzer, Model 5360 equipped with
a Sr-90 electron capture dector.

Column - 1/1+ " Pyrex, 3% DC200 on Chromport XXX

Column Temperature - l82°C

Injector temperature - 235°C

Detector temperature - 2kO°C

Gas - Nitrogen, flow rate lOOcc/min, "

A check on analjrtical results was conducted by determining resi-
dual levels in the same tissue samples by both gas chromatography and
thin-layer chromatography. These data are shown in Table ih. The
variations in residual levels in the same tissue sample as determined
by two different analytical methods indicate that the analytical data
must be viewed as approximate rather than absolute.

Table 7, Total DDT residues (DDE, DDD, DDT) in tissue of experimental hawks with the proportion of
DDE and DDD+DDT expressed as a percentage ot the total.

Brain

Breast muscle

Liver

Total

UUi

/o OI

iTcSXQUc 3.3

DDT

% of residue as

DUX

/o OI

LcSXaUc ELS

residues

DDD+

residues

DDD+

residues

DDD+

Treatment

(ppm)

DDE

DDT

(ppm)

DDE

DDT

(ppm)

DDE

DDT

Fed DDT as

11.03

21.50

16.30

nestlings

Fed DDT as

8.83

27.14

14.55

nestlings and

captives

Fed DDT as

2.76

5.17

2.55

nestlings but

not as captives

■ ' , ''

■■

Table 14- Analytical results when the same tissue was analyzed by two different methods

Residue levels in parts per million wet weight

Gas chromatograph Thin layer chromatograph

Heptachlor Heptachlor
Tissue DDE DDD DDT Dieldrin epoxide DDE DDD DDT Dieldrin epoxide

Egg 10.30 .58 ,75 ,63 =80 10.0 .50 ,50 .50 .50

Brain 40.40 3-00 6.23 1-53 =05 35.00 4,30 8.60 1.80 0

Muscle .20 .13 .062 .017 2.01 .25 .13 .25 0 0

TOTAL DDT RESIDUES (DDT, DDD, DDE) DI EXPERBvIElfi'AL
RED-TAILED liAWCS

Groui") 1

''^ Group k
u

GrojT) 3

Gnuy- 1

P 0)

0) w Grou?:

Groiro

Groun 1

£ Gro;j.-n

•H

Groun

Parts Per Million VJet Weight

-0

'^5

LEGEITD

DEE

DDT + DDD

Group 1. Fed DDT during the nestling period and
sacrificed as fledglings.

Grour) 2,

GrouTD

Fed DDT during the nestling period and
during a i+O-day post -fledgling period
in captivity.

Fed DDT during the nestling period but
were fee "clean" food during a l|0-day
pOGt-fledgling period in captivity.

Table 8. Comparisons of DDT residues (DDE, DDD, DDT) in the

brains of red-tailed hawk nestlings dying of pneumonia
and those sacrificed at the end of the nestling period

No.

Total
DDT

io of residues as

birds

Treatment

residues
(ppm)

DDE

DDD+
DDT

Ratio

Control
(sacrificed)

.96

1+9

Control
(died)

.5^*

Fed DDT**
(sacrificed)

11.03*

1;1

Fed DDT**
(died)

1+9.63

h'.l

* Means

** The dosage was 20 mg DDT/kg body wt every h days

-28-

•

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