To summarize, Adélie penguins, winter denizens of the pack-ice, had their most successful breeding season of the decade in1986-1987, following the heavy pack-ice winter of 1986. Fur-thermore, the winter survival of all age-class cohorts and thepercentage of young 3- to 4-year-olds attempting to breed weresignificantly higher in this season than in either of the twopreceeding mild, ice-free years. Gentoo penguins, in contrast,had very low winter survival this season, for all age cohorts,compared to the 2 previous years, and significantly fewer 2-year-olds attempted to breed this year. Gentoos clearly farebetter during milder winters when they can remain in thevicinity of their breeding rookeries. Chinstraps present some-thing of an enigma. Although they are known to be wintermigrators to the pack-ice, they arrived this spring in very poorbreeding condition (as witnessed by the large number of pre-viously experienced birds that did not attempt to breed) andexperienced low reproductive success; in striking contrast toAdélie penguins. This suggests that Adélies and chinstraps mayhave very different pack-ice wintering areas and/or exploit dif-ferent winter food resources. Much is yet to be learned con-

cerning the nonbreeding season of the Pygoscelis species beforea thorough understanding of their role in the antarctic marineecosystem can be fully comprehended.

Data presented in this paper have not been corrected for bandloss, loss between banding and fledging, or mortality due tobands. Therefore, although they are used to show interestingvariations between years and among age cohorts, they are notvalid for comparisons with other data.

We would like to thank the USAP and the crew of the RIv PolarDuke for logistical help and the X and XI Polish Expeditions fortheir aid and hospitality during our stay at the Polish Academyof Science's Arctowski Station. This research was supported byNational Science Foundation grant DPP 83-14667.

References

Ainley, D.C., R.E. LeResche, and W.J.L. Sladen. 1983. Breeding hiologyofthe Adélie penguin. Berkeley: University of California Press.

Polish X Expedition. 1986. Personal communication.

Hematological parameters of thepenguin genus Pygoscelis of

Antarctica (Adélie, gentoo, andchinstrap)

VIRGINIA A. PARIS ZINSMEISTER and NICOLE VANDERHEYDEN

Department of AnatomySchool of Veterinary Medicine

Purdue UniversityWest Lafayette, Indiana 47907

Hematologic data on wild cogeneric species of penguins havebeen limited to erythrocytic parameters in the Adélie, gentoo,and chinstrap penguins of Antarctica (Block and Murrish 1974;Guard and Murrish 1975; Murrish 1982; Myrcha andKostelecka-Myrcha 1979; Myrcha and Kostelecka-Myrcha 1980;Koselecka-Myrcha and Myrcha 1980). In addition, data fromlimited numbers of captive penguin species have been reported(Schmitt and Righton 1962; Stoskopf, Yarbrough, and Beall1980; Hawkey, Henderson, and Hart 1985).

In 1983, Zinsmeister was invited to accompany scientistsfrom the Instituto Antartico Chileano as part of a researchexpedition to Ardley Island, South Shetlands, Antarctica(62°13'S 58°55'W).

From 9 October to 15 November 1983, blood and tissue sam-ples were obtained from wild adult pygoscelid penguins formorphologic and histochemical analysis (Zinsmeister, Valencia,and Golowasch 1984; Zinsmeister and Valencia 1985). Anti-coagulated blood (sodium EDTA) was collected from four femaleand one male Adélie, five female and one male gentoo, and one

female and one male chinstrap penguins via cardiac punctureduring halothane anesthesia. Sex, maturity, and health statuswere determined post mortem.

Blood films were prepared immediately, air dried, and storedunfixed prior to transport to the United States and subse-quently stained with Wright blood stain.

A 200 cell differential count was performed by the cross-section method on each of two blood smears from each pen-guin. The two values were averaged to determine the finalcount. The percentage of polychromatophils was determinedby evaluating 1,000 red blood cells under oil immersion. Ap-proximately 200 fields (50,000 red blood cells) were observed forhemoparasites.

Data from one female Adélie penguin was discarded due toelevated percentages of monocytes and band heterophils sug-gesting the bird was ill. Data from the four Adélies and sixgentoos were compared for significant differences with stu-dent's "t" test.

Comparisons of the differential counts, and percentages ofpolychromatophils of the three species of Pygoscelis are given inthe table. No significant differences, due to sex or species werenoted for all parameters except monocytes. 1-lemoparasiteswere not observed in any of the blood films.

The leucocytic values for the genus Pygoscelis were similar tothose obtained from other captive species of penguins citedpreviously. In general, the heterophils in penguins are the mostnumerous white cells in the normal peripheral circulation andthis finding contrasts sharply with many other birds, where thelymphocyte is the most frequent leucocyte encountered (Max-well 1978a; Maxwell 1978b; Stoskopf, Neely, and Mangold1983). Elevated numbers of avian heterophils have been shownto result from stress, bacterial infections, and inflammatoryreactions (Burton and Guion 1968; Assoku, Penhale, and Box-ton 1970; Hawkey et al. 1985).

Eosinophils are the second most prevalent granulocytes inpenguins (Stoskopf et al. 1983). Lower numbers of eosinophilswere observed from the chinstrap penguins as compared to the

1987 REVIEW 223

Mean values and ranges for six hematological parametersdetermined for 12 wild pygoscelid penguins from Antarctica

Parameter AdélieGentooChinstrap

Number of birds 462

Differential white blood countHeterophil percentage65.355.361.6

38.5-86.040.8-69.856.0-67.3

Lymphocyte percentage23.937.135.8

7.8-51.826.0-45.027.8-43.8

Eosinophil percentage4.54.00

1.8-7.52.5-7.0

Monocyte percentage39a2.3a2.4

2.5-5.51.0-3.30-4.8

Basophil percentage2.50.90.3

0.8-6.00.3-1.00-0.5

Polychromatophil 1.30.91.5percentage 1.0-2.01.0-2.01.0-2.0

a Significantly different at P < 0.05.

Adélies and gentoos. Avian eosinophilia is often associatedwith hypersensitivity reactions and hemoparasitism (Maxwell1984; Moriya and Ichikawa 1982; Olson 1959).

The percentage of basophils was higher than those reportedfor captive gentoo penguins (Hawkey et al. 1985). In general,avian basophils are the least common granulocyte in the pe-ripheral circulation and usually account for 1 percent of the totalwhite blood count. Our findings may reflect a true physiologicor pathologic difference between captive vs. wild penguins or itmay result from failure of other investigators to recognizebasophils, because they tend to degranulate readily in aqueoussolutions.

Lymphocyte numbers may decrease seasonally or withchronic stress and cortisol/AcTH administration (Stoskopf et al.1983; Siegel 1980; Wingfield, Smith, and Farmer 1984). Lympho-cyte values were similar to previously published values(Hawkey et al. 1985).

Monocytes were more numerous in the Adélies as comparedto the gentoos. Monocytosis has been associated with chronicand tissue destructive diseases (Woerpel and Rosskopf 1984).

The number of polychromatophils in the circulation is relatedto the rate of erythropoiesis. In general, 1-2 percent of avianerythrocytes are polychromatophilic and their increased num-bers are often associated with inflammation and hemorrhage(Campbell and Dein 1984).

Thrombocytes were observed in all blood smears, but theirnumbers were not evaluated.

The authors wish to acknowledge the initial support fromInternational Programs, National Science Foundation grant INT83-14929, Division of Polar Programs, the National ScienceFoundation (round trip air ticket, U.S.A./Chile), and InstitutoAntartico Chileano (travel and expenses, Santiago/Antarctica).

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