DOCSLIB.ORG

Obligate and Facultative Brood Reduction in Eagles: an Examination of Factors That Influence Fratricide

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Obligate and Facultative Brood Reduction in Eagles: an Examination of Factors That Influence Fratricide OBLIGATE AND FACULTATIVE BROOD REDUCTION IN EAGLES: AN EXAMINATION OF FACTORS THAT INFLUENCE FRATRICIDE THOMAS C. EDWARDS,JR. •'2 AND MICHAEL W. COLLOPY3 •Departmentof Biology,University of New Mexico,Albuquerque, New Mexico87131 USA, and 3Schoolof ForestResources and Conservation, 118 Newins-Ziegler Hall, Universityof Florida, Gainesville,Florida 32611 USA ABSTRACT.--Fratricidein eagles (Accipitridae: Accipitrinae) is either obligate[second hatched nestling (C2) always dies] or facultative (C2 occasionallydies) and appearsto be a function of relative size differencesbetween siblings.Several factors,including time between hatch- ing, differencesin hatching weights, and possiblythe sex of the nestling in conjunction with its hatching sequence,influence size difference. Size differencesare modified further by feeding rates of young by adults. These factors determine the relative differencesin locomotordevelopment and coordinationand thus the ability of the first-hatchednestling to control accessto and monopolize parent-provided resources.Significantly greater (P < 0.0001) within-clutch volume differences(an indicator of disparity in hatching weight) and greater time between hatching (mode of 3 versus 2 days) are found in eagles in which fratricide is obligate (three species)than in those in which fratricide is facultative (eight species).We suggestthat these differencesare proximate mechanismsthat accountfor ob- served differencesin the frequencyof fratricide in eagles.Although size differenceis deter- mined in part by the sex and hatching sequenceof the nestling, the role of offspring sex in fratricide is not clear. Received1 November1982, accepted 21 March 1983. IN many speciesof birds the older, dominant factor leading to fratricide. Size difference de- nestling (hereafterreferred to as C1) is instru- termines the ability of a nestling to dominate mental in causing the death of its younger, and outcompete its smaller sibling(s) (Lack subordinate(C2) sibling [e.g. South Polar Skua 1954). As nestlings age and gain weight, size (Catharacta maccormicki),Proctor 1975; Brown difference typically decreases.We suggestthat Booby (Sula leucogaster),Dorward 1962; many fratricide becomesprobable when size differ- speciesof raptors,Meyburg 1974,Stinson 1979]. ence increasesand exceedsa hypothetical frat- The death of C2 may result from direct aggres- ricide threshold. Before this threshold is sion by C1, but more often indirect harassment reached, size difference is such that dominance and intimidationprevent C2 from obtainingthe is indeterminate. This does not imply a lack of resourcesnecessary for growth and survival dominance when only slight differencesexist (e.g. food, brood time). This form of brood re- (see Poole 1979) but rather that the outcome of duction, termed fratricide, is observedin many sibling aggressiveinteractions may vary. Nei- birds of prey. Within this group, it is mostcom- ther sibling can effectively dominate the other. mon in eagles(Accipitridae: Accipitrinae) with Fratricide is unlikely unless size difference is a clutch size of two. Published literature sug- great enough to ensure exclusion of C2 from geststhere are two categoriesof fratricide:an parent-provided resources.For theoretical con- obligateform where C2 invariably diesas a re- siderations of fratricide see O'Connor (1978) and suit of fratricide, and a facultative form where Stinson (1979). C2 occasionally dies (Table 1). Size difference is a function of several factors The relative size difference of siblings (cal- acting in concert. Here, using Golden Eagles culated as Dt/weight C2, where Dt = sibling (Aquilachrysaetos) as a test species,we examine weight difference) is an important proximate several factors that we feel are important in understanding fratricide in eagles. We have used data from the literature, museum speci- 2 Present address: School of Forest Resources and mens, field studies, and, where available, from Conservation, 118 Newins-Ziegler Hall, University other eagles. Comparisons also are made be- of Florida, Gainesville, Florida 32611 USA. tween the eaglesgrouped in the two categories 630 The Auk 100: 630-635. July 1983 July 1983] Fratricidein Eagles 631 TABLE1. Speciesof eaglesexhibiting either obligoteor facultative fratricide as defined in text. Type of Species fratricidea Hatch intervalb Source Crowned Eagle O 3 Brown and Amadon (1968) (Stephanoaetuscoronatus) Verreaux's Eagle O 3 Meyburg (1974) (Aquila verreauxii) Brown and Amadon (1968) Lesser-spottedEagle O 3-4 Meyburg (1974) (A. pomarina) Brown and Amadon (1968) Greater-spottedEagle F 2 Brown and Amadon (1968) (A. clanga) Tawny Eagle F "several days" Brown and Amadon (1968) (A. rapax) Imperial Eagle F 2 Brown and Amadon (1968) (A. heliaca) Golden Eagle F 2 Brown and Amadon (1968) (A. chrysaetos) This study Wedge-tailed Eagle F 1-4 Brown and Amadon (1968) (A. audax) African Hawk Eagle F 3 Brown (1952) (Hieraaetusfasciatus) BootedEagle F "several days" Brown and Amadon (1968) (H. pennatus) Bald Eagle F 2 Brown and Amadon (1968) (Haliaeetusleucocephalus) O - obligate, F facultative. Represents mode in days. of fratricide to determine whether or not pos- establishesdominance with a minimum of ag- sible differencesin proximate mechanismscan gressiveinteractions. Both Meyburg (1974) and account for the observed differences in the fre- Newton (1977) consider hatch interval and its quency of fratricide. effect on size difference an important factor in fratricide. METHODS AND RESULTS One result of hatching asynchronyin eagles is the establishment of a feeding hierarchy Hatchinterval.--Comparing the categoriesof among the young whereby C1 can control ac- fratricide reveals that, in general, hatching in- cessto the female and feed first (Meyburg 1974, terval is greater when fratricide is obligate Collopy 1980). The presentationof food to the rather than facultative (Table 1). The effect of young in small,easily controlled bits allows C1 time between hatching on size difference can to deny C2 accessto the female and to ensure be seen in a comparison of 1-, 2-, and 3-day adequatefood for itself. As C1 becomessatiat- hatch intervals in 12 broods of Golden Eagles ed, its response to a begging attempt by C2 studied in southwesternIdaho (Fig. 1). Nest- becomesless aggressive.An analysisof time- ling weight measurements,used to determine lapse photography and over 1,950 h of brood- size difference,were taken every 4-6 days dur- rearing observationsfrom blinds showed that ing brood rearing (Kochert 1972,Collopy 1980). parentsmade no effort to distributefood equal- The percentagesize difference was calculated ly between the nestlingsand did not interfere from sibling weight difference/weightC2. Note where C1 responded aggressivelytoward C2 that the peak value in size difference increases (Collopy 1980). Thus, if feeding ratesare low, as time between hatching increases.Although siblings do not receive equal sharesof food, not examined here, the intensity of sibling and C2, receiving less, will exhibit slower aggressionis probably greater when size dif- growth than C1. Relative size difference can ference is small and dominance less determi- rapidly increase. nate (D. Mock, pers. comm.).A large difference Hatching weight.--Data on differences in 632 EDWARDSAND COLLOPY [Auk,Vol. 100 FEMALE-FEMALE FEMALE-MALEC 20 MALE-FEMALE AH=[ do •'o AGE OF C2 (DAYS) Fig. 1. Effectof nestlingsex, hatching sequence, and time betweenhatching on siblingsize difference in 12 broodsof Golden Eaglesin southwesternIdaho. Arrows on horizontalaxes indicate point in a particular broodwhere siblingsapproach equality in size.Note verticalscale difference in Fig. lb. hatching weights of sibling eaglesare limited. weight properly, one should know the laying The lower relative hatching weight of C2 is sequencein each museum egg set. Except for documented for Verreaux's Eagle (Aquila ver- Verreaux's Eagle, however, this information is reauxii;Gargett, unpubl. data) and the African unavailable. Thus, our results represent a mag- Hawk Eagle(Hieraaetus fasciatus; Meyburg 1974) nitude of volume difference within a clutch, and is suggestedfor other large eagles (New- and, although inappropriate for testing hy- ton 1977). One possible indicator of hatching pothesesregarding hatch-weight differencesin weight is egg volume (seeParsons 1970, Howe particular species, the results can be used to 1976). Egg-volume data were obtained from comparepotential hatch-weight differencesbe- museum specimensfor eight speciesof eagles tween eaglesin which fratricide is obligate and exhibiting facultative fratricide and three those in which it is facultative. This compari- speciesin which fratricide is obligate. Volume son shows that significant differencesdo exist: was estimated from the equation V = 0.51LB2, those speciesin which fratricide is obligate ex- where L = length and B = breadth of the egg hibit greater within-clutch volume difference (Hoyt 1979). The equation (volume difference than do those defined as facultaive (n = 11, P < between eggs/volume smaller egg) was used to 0.0001, Kruskal-Wallis single-factortest). calculate the percentageof volume difference Nestlingsex and hatching sequence.--In a brood within each museum clutch examined (Table in which both nestlings obtain sufficient food 2). to maintain maximum growth, size difference To test the effect of difference in hatching peaksslightly after C2 hatches,then decreases July 1983] Fratricidein Eagles 633 TABLE2. Analysis of within-clutch egg-volume difference for eagles exhibiting
Load more

Recommended publications
  • A Multi-Gene Phylogeny of Aquiline Eagles (Aves: Accipitriformes) Reveals Extensive Paraphyly at the Genus Level
    Available online at www.sciencedirect.com MOLECULAR SCIENCE•NCE /W\/Q^DIRI DIRECT® PHYLOGENETICS AND EVOLUTION ELSEVIER Molecular Phylogenetics and Evolution 35 (2005) 147-164 www.elsevier.com/locate/ympev A multi-gene phylogeny of aquiline eagles (Aves: Accipitriformes) reveals extensive paraphyly at the genus level Andreas J. Helbig'^*, Annett Kocum'^, Ingrid Seibold^, Michael J. Braun^ '^ Institute of Zoology, University of Greifswald, Vogelwarte Hiddensee, D-18565 Kloster, Germany Department of Zoology, National Museum of Natural History, Smithsonian Institution, 4210 Silver Hill Rd., Suitland, MD 20746, USA Received 19 March 2004; revised 21 September 2004 Available online 24 December 2004 Abstract The phylogeny of the tribe Aquilini (eagles with fully feathered tarsi) was investigated using 4.2 kb of DNA sequence of one mito- chondrial (cyt b) and three nuclear loci (RAG-1 coding region, LDH intron 3, and adenylate-kinase intron 5). Phylogenetic signal was highly congruent and complementary between mtDNA and nuclear genes. In addition to single-nucleotide variation, shared deletions in nuclear introns supported one basal and two peripheral clades within the Aquilini. Monophyly of the Aquilini relative to other birds of prey was confirmed. However, all polytypic genera within the tribe, Spizaetus, Aquila, Hieraaetus, turned out to be non-monophyletic. Old World Spizaetus and Stephanoaetus together appear to be the sister group of the rest of the Aquilini. Spiza- stur melanoleucus and Oroaetus isidori axe nested among the New World Spizaetus species and should be merged with that genus. The Old World 'Spizaetus' species should be assigned to the genus Nisaetus (Hodgson, 1836). The sister species of the two spotted eagles (Aquila clanga and Aquila pomarina) is the African Long-crested Eagle (Lophaetus occipitalis).
    [Show full text]
  • Effect of Environmental Elements on Migration Pattern of Eagles at Jorbeer Conservation Reserve, Bikaner, Rajasthan, India
    Kataria et al RJLBPCS 2016 www.rjlbpcs.com Life Science Informatics Publications Original Research Article DOI - 10.26479/2016.0203.08 EFFECT OF ENVIRONMENTAL ELEMENTS ON MIGRATION PATTERN OF EAGLES AT JORBEER CONSERVATION RESERVE, BIKANER, RAJASTHAN, INDIA A.K. Kataria1*, N.Kataria2 and R.N.Kumawat3 1.Principal Investigator, Centre for excellence for use of space based technology in animal science, Rajasthan University of Veterinary and Animal Sciences, Bikaner-334001, Rajasthan, India. 2.Professor & Head, Department of Veterinary Physiology, College of Veterinary and Animal Science, Rajasthan University of Veterinary and Animal Sciences, Bikaner-334001, Rajasthan, India. 3. Deputy Forest Officer (Wildlife), Bikaner, Rajasthan ABSTRACT: The present endeavor was carried out to find out the effect of environmental elements on migration pattern of eagles at Jorbeer Conservation Reserve, Bikaner, Rajasthan, India (JCRBRI) during period from April 2015 to July 2016. The eagles studied were steppe eagle (Aquila nipalensis) and greater spotted eagle (Clanga clanga). The greater spotted eagle was seen only from November to February reiterating their winter migration to this reserve. Steppe eagle stayed at reserve during various months of the study year 2015 and 2016 when the THI values varied as 56.64-79.5. Recording of count of steppe eagle and greater spotted eagle besides real-time observation of environmental temperature and humidity signified in monitoring of eagle residence in the region. Result of the endeavor assisted in comprehending the absence of eagles in summer months during study periods. Residential period of steppe eagle was from November to April and of greater spotted eagle was from November to February only.
    [Show full text]
  • Uncorrected Proof
    Policy and Practice UNCORRECTED PROOF BBarney_C011.inddarney_C011.indd 117979 99/13/2008/13/2008 44:11:24:11:24 PPMM UNCORRECTED PROOF BBarney_C011.inddarney_C011.indd 118080 99/13/2008/13/2008 44:11:24:11:24 PPMM Copy edited by Richard Beatty 11 Conservation Values from Falconry Robert E. Kenward Anatrack Ltd and IUCN-SSC European Sustainable Use Specialist Group, Wareham, UK Introduction Falconry is a type of recreational hunting. This chapter considers the conser- vation issues surrounding this practice. It provides a historical background and then discusses how falconry’s role in conservation has developed and how it could grow in the future. Falconry, as defi ned by the International Association for Falconry and Conservation of Birds of Prey (IAF), is the hunting art of taking quarry in its natural state and habitat with birds of prey. Species commonly used for hunt- ing include eagles of the genera Aquila and Hieraëtus, other ‘broad-winged’ members of the Accipitrinae including the more aggressive buzzards and their relatives, ‘short-winged’ hawks of the genus Accipiter and ‘long-winged’ falcons (genus Falco). Falconers occur in more than 60 countries worldwide, mostly in North America, the Middle East, Europe, Central Asia, Japan and southern Africa. Of these countries, 48 are members of the IAF. In the European Union falconry Recreational Hunting, Conservation and Rural Livelihoods: Science and Practice, 1st edition. Edited by B. Dickson, J. Hutton and B. Adams. © 2009 Blackwell Publishing, UNCORRECTEDISBN 978-1-4051-6785-7 (pb) and 978-1-4051-9142-5 (hb). PROOF BBarney_C011.inddarney_C011.indd 118181 99/13/2008/13/2008 44:11:24:11:24 PPMM Copy edited by Richard Beatty 182 ROBERT E.
    [Show full text]
  • Avian Taxonomy
    Length (cm) Wing span (cm) Weight (gms) cluch size incubation fledging Notes TAXONOMY male female male female male female (# eggs) (days) (days) Falconiformes Accipitridae (vultures, hawks, eagles) short rounded wings; long tail; light eyes ACCIPITRINAE (true hawks) Accipiter cooperii (Cooper's hawk) 39 45 73 84 341 528 3-5 30-36 (30) 25-34 crow sized; strongly banded tail; rounded tail Accipiter gentilis (Northern goshawk) 49 58 101 108 816 1059 2-4 28-38 (33) 35 square tail; most abundant NAM hawk; proportionaly 26 31 54 62 101 177 4-5 29 30 Accipiter striatus (sharp-shinned hawk) strongest foot Accipiter nisus (Eurasian sparrowhawk ) 37 37 62 77 150 290 5-Apr 33 27-31 Musket BUTEONINAE (broadwings) Buteo (buzzards or broad tailed hawks) Buteo regalis (ferruginous hawk) 53 59 132 143 1180 1578 6-Apr 34 45-50 Buteo lineatus (red-shouldered hawk) 47 53 96 105 550 700 3-4 28-33 42 square tail Buteo jamaicensis (red-tailed hawk) 48 55 114 122 1028 1224 1-3 (3) 28-35 (34) 42-46 (42) (Harlan' hawk spp); dark patagial featehres: immature; Parabuteo Parabuteo cuncincutus (Harris hawk) 47 52 90 108 710 890 2-4 31-36 45-50 reddish orange shoulders Sea Eagles Haliaeetus leucocephalus (bald eagle) 82 87 185 244 3000 6300 1-3 35 70-92 True Eagles Aquila chrysaetos (golden eagle) 78 82 185 220 3000 6125 1-4 (2) 40-45 50 white patches on wings: immature; CIRCUS Circus cyaneus (Northern harrier) 46 50 93 108 350 530 4-6 26-32 30-35 hovers; hunts by sound Falconidae (falcons) (longwings) notched beak Falco columbarius (American merlin) 26 29 57 64
    [Show full text]
  • Family Break Up, Departure, and Autumn Migration in Europe of A
    462 SHORT COMMUNICATIONS VOL. 39, NO. 4 j RaptorRes. 39(4):462-466 ¸ 2005 The Raptor ResearchFoundation, Inc. FAMILY BREAKUP, DEPARTURE,AND AUTUMN MIGRATION IN EUROPE OF A FAMILY OF GREATERSPOTTED EAGLES (AQUILA CIANGA) AS REPORTEDBY SATELLITETELEMETRY BERND-U. MEYBURG 1 WorldWorking Group on Birdsof Prey,Wangenheimstr. 32, D-14193 Berlin, Germany CHRISTIANE MEYBURG WorldWorking Group on Birdsof Prey,31 Avenuedu Maine, F-75015 Paris,France TADEUSZ MIZERA AND GRZEGORZ M•CIOROWSKI AgriculturalUniversity, Zoology Department, Wojska Polskiego 71C, 60-625Poznan, Poland JAN KOWALSKI Gugny2, 19-104 Trzcianne,Poland KEYWORDS: GreaterSpotted Eagle; Aquila clanga; depar- Terminals, PTTs) in the Biebrza river valleyof northeast- ture;family breakup; migration;satellite telemetry. ern Poland. The eagle nestwas located in a National Park protecting the largest peatlands in Central Europe, in- cluding 15547 ha of forests,18 182 ha of agricultural The transition of birds of prey to independenceis dif- land, and 25 494 ha of wetlands--the Biebrza marshes. ficult to study (Brown and Amadon 1968), as both old More than 70 natural and semi-naturalplant associations and young birds stray ever further from the nest site to- have been documented in the Biebrza valley.The most ward the end of the post-fledgingperiod. We know of no dominant forest associations include black alder (Alnus studyconcerning a raptor speciesin which the departure glutinosa),swampy birch (Betulapubescens), and peat co- on migration, the break up of the family,and subsequent niferousforests (Salici-Betuletum). Frequent anthropogen- migration have been investigated by satellite tracking. ic ecosystemsfound in the valley are pastures,cultivated Here, we report on a case concerning Greater Spotted groundsand urbanized areas.One of the greatestthreats Eagles (Aquila clanga).Available information on this spe- to the park is human modified drainagepatterns, which cies is limited, but Ivanov et al.
    [Show full text]
  • Compendium of Avian Ecology
    Compendium of Avian Ecology ZOL 360 Brian M. Napoletano All images taken from the USGS Patuxent Wildlife Research Center. http://www.mbr-pwrc.usgs.gov/id/framlst/infocenter.html Taxonomic information based on the A.O.U. Check List of North American Birds, 7th Edition, 1998. Ecological Information obtained from multiple sources, including The Sibley Guide to Birds, Stokes Field Guide to Birds. Nest and other images scanned from the ZOL 360 Coursepack. Neither the images nor the information herein be copied or reproduced for commercial purposes without the prior consent of the original copyright holders. Full Species Names Common Loon Wood Duck Gaviiformes Anseriformes Gaviidae Anatidae Gavia immer Anatinae Anatini Horned Grebe Aix sponsa Podicipediformes Mallard Podicipedidae Anseriformes Podiceps auritus Anatidae Double-crested Cormorant Anatinae Pelecaniformes Anatini Phalacrocoracidae Anas platyrhynchos Phalacrocorax auritus Blue-Winged Teal Anseriformes Tundra Swan Anatidae Anseriformes Anatinae Anserinae Anatini Cygnini Anas discors Cygnus columbianus Canvasback Anseriformes Snow Goose Anatidae Anseriformes Anatinae Anserinae Aythyini Anserini Aythya valisineria Chen caerulescens Common Goldeneye Canada Goose Anseriformes Anseriformes Anatidae Anserinae Anatinae Anserini Aythyini Branta canadensis Bucephala clangula Red-Breasted Merganser Caspian Tern Anseriformes Charadriiformes Anatidae Scolopaci Anatinae Laridae Aythyini Sterninae Mergus serrator Sterna caspia Hooded Merganser Anseriformes Black Tern Anatidae Charadriiformes Anatinae
    [Show full text]
  • Repeated Sequence Homogenization Between the Control and Pseudo
    Repeated Sequence Homogenization Between the Control and Pseudo-Control Regions in the Mitochondrial Genomes of the Subfamily Aquilinae LUIS CADAH´IA1*, WILHELM PINSKER1, JUAN JOSE´ NEGRO2, 3 4 1 MIHAELA PAVLICEV , VICENTE URIOS , AND ELISABETH HARING 1Molecular Systematics, 1st Zoological Department, Museum of Natural History Vienna, Vienna, Austria 2Department of Evolutionary Ecology, Estacio´n Biolo´gica de Don˜ana, Sevilla, Spain 3Centre of Ecological and Evolutionary Synthesis (CEES), Department of Biology, Faculty for Natural Sciences and Math, University of Oslo, Oslo, Norway 4Estacio´n Biolo´gica Terra Natura (Fundacio´n Terra Natura—CIBIO), Universidad de Alicante, Alicante, Spain ABSTRACT In birds, the noncoding control region (CR) and its flanking genes are the only parts of the mitochondrial (mt) genome that have been modified by intragenomic rearrangements. In raptors, two noncoding regions are present: the CR has shifted to a new position with respect to the ‘‘ancestral avian gene order,’’ whereas the pseudo-control region (CCR) is located at the original genomic position of the CR. As possible mechanisms for this rearrangement, duplication and transposition have been considered. During characterization of the mt gene order in Bonelli’s eagle Hieraaetus fasciatus, we detected intragenomic sequence similarity between the two regions supporting the duplication hypothesis. We performed intra- and intergenomic sequence comparisons in H. fasciatus and other falconiform species to trace the evolution of the noncoding mtDNA regions in Falconiformes. We identified sections displaying different levels of similarity between the CR and CCR. On the basis of phylogenetic analyses, we outline an evolutionary scenario of the underlying mutation events involving duplication and homogenization processes followed by sporadic deletions.
    [Show full text]
  • Winter Ranging Behaviour of a Greater Spotted Eagle (Aquila
    Slovak Raptor Journal 2014, 8(2): 123–128. DOI: 10.2478/srj-2014-0014. © Raptor Protection ofSlovakia (RPS) Winter ranging behaviour of a greater spotted eagle (Aquila clanga) in south- east Spain during four consecutive years Zimné teritoriálne správanie orla hrubozobého (Aquila clanga) v juhovýchodnom Španiel- sku počas štyroch za sebou nasledujúcich rokov Juan M. PÉREZ-GARCÍA, Urmas SELLIS & Ülo VÄLI Abstract: Knowing the winter behaviour is essential for deciding on conservation strategies for threatened migratory species such as the greater spotted eagle (Aquila clanga). Fidelity and inter-annual variation in winter home range of an Estonian greater spotted eagle were studied during the first four years of its life by means of GPS satellite telemetry in south-eastern Spain. Results show the eagle exploited a small area (12.7 km2, 95% kernel) with high inter-annual fidelity during all winter stages. The A. clanga preferred marshes and water bodies and avoided irrigated crops and urban areas. Waterfowl hunting did not show any effect on the spatial pattern of the eagle’s behaviour, although water level management in reservoirs could influence their use by the A. clanga. Our study highlights that the wintering home range may be limited to a small suitable habitat patch where human activities, especially water reservoir management, should be regulated. Abstrakt: Nevyhnutným predpokladom efektívnych ochranárskych opatrení je poznanie zimného správania ohrozeného mi- grujúceho druhu, akým je orol hrubozobý (Aquila clanga). Fidelita a medziročná variabilita charakteristík zimného okrsku jedinca orla hrubozobého pochádzajúceho z Estónska sa sledovala počas prvých štyroch rokov jeho života pomocou GPS-satelit- nej telemetrie v juhovýchodnom Španielsku.
    [Show full text]
  • Information on Haliaeetus Leucocephalus
    ADW: Haliaeetus leucocephalus: Information Page I of 5 University of Michigan Museum of Zoology Structured Inquiry Searcl Home > Kingdom Animalia >- Phylum Chordata U Subphylum Vertebrata ,> Class Aves1 Order Falconiformes t- Family Accipitridae P Subfamily Accipitrinae r Species Haliaeetus leucocephalus Haliaeetusleucocephalus bald eagle Information Pictures I4-0Classification I 2008/01/20 04:31:08.826 US/Eastern By Marie S. Harris Geographic Range Kingdom: Animalia Phylum: Chordata Subphylum: Vertebrata Class: Aves Order: Falconiformes Family: Accipitridae Subfamily: Accipitrinae Genus: Haliaeetus Species: Haliaeetus leucocephallus The bald eagle is native to North America and originally bred from central Alaska and northern Canada south to Baja California, central Arizona, and the Gulf of Mexico. It now has been extirpated in many southern areas of this range. Biogeographic Regions: nearctic CL (native (k). Habitat Bald eagles are able to live anywhere on the North American continent where there are adequate nest trees, roosts ands feeding grounds. Open water such as a lake or an ocean, however, is a necessity. Terrestrial Biomnes: desert or dune Ck; savanna or grassland Q,; chaparral Q,; forest Q.; mountains Q. http://animaldiversity.ummz.umich.edu/site/accounts/information/Haliaeetus-leucoceph... 1/23/2008 ADW: Haliaeetus leucocephalus: Information Page 2 of 5 Physical Description Mass 3175 g (average) [Ref] (111.76 oz) The plumage of an adult bald eagle is brown with a white head and tail. Immature eagles are irregularly mottled with white until the fourth year. Their legs are feathered half way down the tarsus, and the beak, feet, and eyes are bright yellow. Bald eagles have massive tarsi, short and powerful grasping toes, and long talons.
    [Show full text]
  • Wave Moult of the Primaries in Accipitrid Raptors, and Its Use in Ageing Immatures
    Chancellor, R. D. & B.-U. Meyburg eds. 2004 Raptors Worldwide WWGBP/MME Wave Moult of the Primaries in Accipitrid raptors, and its use in ageing immatures William S. Clark ABSTRACT Stresemann & Stresemann (1966) described wave moult in the primary remiges ('Staffelmauser' in German; also translated as 'step-wise moult') for some families of birds but not for Acccipitrid raptors, even though many of the species in this family (especially the larger ones) show it. Primaries of Accipitrid raptors are replaced from Pl (inner) sequentially outward. Waves are formed when not all of the ten primaries are replaced in any annual moult cycle. In the next annual cycle, moult begins anew at Pl as well as continuing with the next feather from where it left off in the last cycle. Two or three, occasionally four, wave fronts of new primaries can be seen in the primaries of some raptors, especially larger ones, e.g., eagles. Knowledge and understanding of wave moult can ascertain the ages of immature raptors in those species that take three or four years to attain adult plumage, as these species typically do not replace all of the primaries in any moult cycle. Juvenile eagles show all primaries the same age. Second plumage eagles show two ages of primaries, newer inner ones and older retained juvenile outer ones. Third plumage eagles show two waves, with the first wave proceeding to P8, P9, or PIO, and the second to P3, P4, P5, or P6. Fourth plumage eagles usually show new outer PlO from the first wave, new P5 to P7 from the second wave, and new Pl to P3 from the most recent wave.
    [Show full text]
  • North American Buteos with This Charac- Seen by Many Birders but Did Not Return the Next Year
    RECOGNIZING HYBRIDS “What is that bird?” How many times have we heard this question or something similar while out birding in a group? The bird in question is often a raptor, shorebird, flycatcher, warbler, or some other hard-to-distinguish bird. Thankfully, there are excellent field guides to help us with these difficult birds, including more- specialized guides for difficult-to-identify families such as raptors, war- blers, gulls, and shore- birds. But when we en- counter hybrids in the field, even the specialty guides are not sufficient. Herein we discuss and present photographs of four individuals that the three of us agree are interspecific hybrids in the genus Buteo. Note: In this article, we follow the age and molt terminology of Howell et al. (2003). Fig. 1. Hybrid Juvenile Hybrid 1 – Juvenile Rough-legged × Swainson’s Hawk Swainson’s × Rough- This hybrid (Figs. 1 & 2) was found by MR, who first noticed it on the legged Hawk. Wing shape morning of 19 November 2002 near Fort Worth, Texas. The hunting hawk is like that of Swainson’s was seen well and rather close up, both in flight and perched. An experi- Hawk, with four notched primaries. But the dark carpal enced birder, MR had never seen a raptor that had this bird’s conflicting patches, the dark belly-band, features: Its wing shape was like that of Swainson’s Hawk, but it had dark the white bases of the tail carpal patches and feathered tarsi, like those of Rough-legged Hawk. MR feathers, and the feathered placed digiscoped photos of this hawk on his web site <www.
    [Show full text]
  • The Eagle Genus Hieraaetus Is Distinct from Aquila, with Comments on the Name Ayres’ Eagle
    William S. Clark 295 Bull. B.O.C. 2012 132(4) The eagle genus Hieraaetus is distinct from Aquila, with comments on the name Ayres’ Eagle by William S. Clark Received 16 April 2012 Consensus has long existed among taxonomists as to the placement of the species of the eagles in the genera Aquila and Hieraaetus, the only exception being Wahlberg’s Eagle, which has been treated either as A. wahlbergi or H. wahlbergi. However, recent comparisons of DNA sequences of these eagles revealed that both genera were polyphyletic (Helbig et al. 2005, Lerner & Mindell 2005, Griffiths et al. 2007, Haring et al. 2007). To ensure monophyly, these authors recommended that some species be moved into and out of both genera and placed Wahlberg’s Eagle definitely in Hieraaetus. On the other hand, Sangster et al. (2005) recommended that Hieraaetus be subsumed into Aquila, for which they cite eight recent phylogenetic studies, only four of them published in peer-reviewed journals (Roulin & Wink 2004, Bunce et al. 2005, Helbig et al. 2005, Lerner & Mindell 2005); all of which, nevertheless, retained Hieraaetus. Thus, none of the four peer-reviewed journal articles cited by Sangster et al. (2005) to justify placing Hieraaetus into Aquila actually recommended this. Further, Sangster et al. (2005) proposed only that Booted Eagle (pennatus) be included in Aquila, because their recommendations only considered European birds. The generic treatment of Sangster et al. (2005) was followed without comment by Gjershaug et al. (2009) in describing Weiske’s or Pygmy Eagle (weiskei) as a species separate from Little Eagle H.
    [Show full text]