Catalog of Brown-Headed Cowbird Hosts from Iowa
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View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by University of Northern Iowa Proceedings of the Iowa Academy of Science Volume 92 Number Article 4 1985 Catalog of Brown-headed Cowbird Hosts from Iowa Peter E. Lowther University of Northern Iowa Copyright ©1985 Iowa Academy of Science, Inc. Follow this and additional works at: https://scholarworks.uni.edu/pias Recommended Citation Lowther, Peter E. (1985) "Catalog of Brown-headed Cowbird Hosts from Iowa," Proceedings of the Iowa Academy of Science, 92(3), 95-99. Available at: https://scholarworks.uni.edu/pias/vol92/iss3/4 This Research is brought to you for free and open access by the Iowa Academy of Science at UNI ScholarWorks. It has been accepted for inclusion in Proceedings of the Iowa Academy of Science by an authorized editor of UNI ScholarWorks. For more information, please contact [email protected]. Lowther: Catalog of Brown-headed Cowbird Hosts from Iowa Proc. Iowa Acacl. Sci. 92(3):95-99, 1985 Catalog of Brown-headed Cowbird Hosts from Iowa PETER E. LOWTHER Department of Biology, University of Northern Iowa, Cedar Falls, Iowa 50614 USA A survey o~lite.rature, egg collections and field data produced a list of 60 species that have served as hosts of the brood parasitic Brown head~. Cowb1r~ m Iowa. About 52 of these species are known to have reared cowbird young. In Iowa, those species most commonly ~~t1zed- m a~solute_numbe~ - incl_ude Red-winged Blackbirds, Dickcissels, Common Yellowthroats and Song Sparrows. An addmonal 36 species are listed whICh nest m Iowa but have not yet been recorded as cowbird hosts in the state even though they have served as cowbird hosts elsewhere. INDEX DESCRIPTORS: Brood parasitism, Brown-headed Cowbird, cowbird hosts, Iowa, Molothrus ater The Brown-headed Cowbird (Molothrus ater [Boddaert]) is a wide ly to his 1963 work with additional data from Friedmann ( 1971) and ranging brood parasite in North America. The species is not host Friedmann et al. ( 1977). Often, not much more than " ... Iowa ... " specific, thus cowbirds interact with geographically varying host appears in Friedmanns accounts but any specific citation he gave I also communities. Friedmann (1929, 1963, 1971, Freidmann et al. include below. Each species account begins with a notation indicating 1977) has compiled host records for cowbirds and most recently listed total number of parasitism records tabulated by Friedmann and over 200 species that have had cowbird eggs in their nests. Friedmann frequency at which the species has been noted to rear cowbird young indicated regional differences in host communities by listing states (cf. Friedmann 1963:39-41). In addition, Iowa Nest Record Card and provinces from which parasitism records came. I have con data are summarized briefly. A species account may begin, for solidated the Iowa records from Friedmann's works and have added example, with F: 57, 2; NC: 2 of 18. This would mean Friedmann new records of cowbird hosts in Iowa. In addition to reports from the compiled 57 records of parasitism and 2 cases of cowbird young being literature, data from the collections of7 museums have provided Iowa reared and of 18 nest cards, 2 were of parasitized nests. In most cases, records (see Acknowledgements for abbreviations) and Iowa's Nest Friedmann described incidence of rearing cowbird young as "frequent Record Card Program has reports on 152 parasitized nests collected ly" or "several times" rather than giving an actual number. Details of through 1982 (Newhouse and Ehresman 1982, 1983). parasitism records known from Iowa comprise the remainder of each In an early account of the birds of Iowa, Savage ( 1894a) provided a species' account. list of 3 1 host species compiled from information provided by J. E. Mourning Dove, Zenaida macroura (Linnaeus). - F: 8, O; NC: 0 of law, R. M. Anderson, J. V. Crone and himself. Later (Savage 1897) 378. Friedmann cited Coues' ( 1884) report of a parasitism record from he gave an account of his acquaintance with Brown-headed Cowbirds Iowa. in Henty County. He listed 25 species of cowbird hosts and reported Eastern Wood-Pewee, Contopus virens (Linnaeus). - F: 50 + , O; extreme dates of cowbird egg laying activity as 22 April and 27 July. NC: 0of1. Savage (1894a, 1897) listed the Eastern Wood-Pewee as Anderson (1907) added 10 species to Savage's (1897) host list. Studies an Iowa host. of cowbirds and their hosts in Iowa are few and are limited often to Acadian Flycatcher, Empidonax virercens (Vieillot). -F: 45, "several anecdotal reports or observations incidental to studies of other species. times"; NC: 1 of 18. The nest card record is of a nest found by D. D. Brown-headed Cowbirds are common in Iowa (Dinsmore 1981; Table 1). Despite their abundance, their breeding biology has been little studied in the state (see species accounts below). To some extent, Table 1. List of most common passerines in Iowa based on this is understandable since cowbirds are brood parasites and their Breeding Bird Survey (F&WS) data (Dinsmore 1981). nesting efforts are scattered about in the nests of many host species. This consolidation of cowbird host records can serve as a recent Birds/ reference for field workers in the state and encourage observations and Species route Comments reports on the breeding biology of Brown-headed Cowbirds and their interactions with host species. House Sparrow 176.4 Not host due to Of the many species recorded as cowbird hosts, those most habitat, cavity nest Red-winged Blackbird 172.0 important - in terms of numbers of cowbird young reared - are Western Meadowlark 69.2 likely common species. Dinsmore ( 1981) listed the most common Dickcissel 62.0 species recorded on Breeding Bird Survey routes in Iowa. Among the European Starling 60.2 Not host due to passerines on this list (Table 1) are 6 species that are likely the most habitat, cavity nest important hosts in Iowa for nesting cowbirds. Only for two species are Common Grackle 57.0 Not host due to? there Iowa data on cowbird-host interactions. Data are skimpy for the Barn Swallow 32.2 Not host due to habitat other four species but on the basis of other midwest studies these or nest location species are likely important cowbird hosts in Iowa. These species (and American Robin 31. 5 Not host due to ?; ejector studies which have shown their interactions with cowbirds) are Red Common Yellowthroat 24.7 American Crow 22.6 Not host due to large size winged Blackbird (see account below), Dickcissel (Zimmerman BROWN-HEADED COWBIRD 20.5 1983), Common Yellowthroat (Hofslund 1957), Song Sparrow (Nice Song Sparrow 17.6 1937), Eastern Meadowlark (Elliott 1978), and Vesper Sparrow (see Eastern Meadowlark 15.6 account below). Horned Lark 14.7 House Wren 14.6 Not host due to cavity nest SPECIES ACCOUNTS Vesper Sparrow 12.8 American Goldfinch 11.6 Not host due to late In the following accounts, my citation of Friedmann refers primari- season nesting Published by UNI ScholarWorks, 1985 1 Proceedings of the Iowa Academy of Science, Vol. 92 [1985], No. 3, Art. 4 96 PROC. IOWA ACAD. SCI. 92(1985) Koenig in Van Buren County on 29 May 1979. cowbird eggs (Rothstein 1975). Willow Flycatcher, Empidonax traillii (Audubon). - F: 150, Gray Catbird, Dumetella carolinensis (Linnaeus). - F: 39, 2; NC: 3 "several times"; NC: O of 2. Most of Friedmann's records on "Traill's" of97. J.E. Law (in Savage 1894a) listed catbirds as cowbird hosts as Flycatcher refer to the Willow Flycatcher (Friedmann et al. 1977: 13). did Polderboer (1939). Johnson and Best (1980) found 1 nest (of a In Iowa, Savage (1894a; Anderson 1907) described a nest with a total of 37) parasitized; this egg was ejected by the catbirds, a usual buried cowbird egg. Lowther (1983) found 2 parasitized nests in practice of Gray Catbirds (Rothstein 1975). Dix (1936) reported on a Dickinson County. parasitized catbird nest from which the cowbird egg was ejected. Least Flycatcher, Empidonax minimus (Baird and Baird). F: 39, O; Brown Thrasher, Toxostoma rufum (Linnaeus). - F: 79, "several NC: O of O. Iowa's mention in Friedmann's account was based, times"; NC: 3 of 113. Baird et al. (1875) mentioned a thrasher nest probably, on R. M. Anderson's host list (in Savage 1894a) and his later that reared a cowbird; another nest that produced a cowbird was work (Anderson 1907). described by Lowther (1983). Keyes and Williams (1888), J. E. Law Eastern Phoebe, Sayornis phoebe (Latham). - F: 600, "frequently"; (in Savage 1894a), Stoner ( 1919) and Polderboer (1939) reported NC: 0 of 8. Published accounts of phoebes as hosts include Brown Brown Thrashers as cowbird hosts. Brown Thrashers usually eject (1964), Hodges (1954), and Stoner (1919). cowbird eggs (Rothstein 1975). Eastern Kingbird, Tyrannus tyrannus (Linnaeus). -F: 24, 1; NC: 0 Cedar Waxwing, Bombycilla cedrorum Vieillot. - F: 80, "several of 20. Savage (1894a:36, 1897:6) and Anderson (1907:299-300) times"; NC: 1 of8. The single nest card report by A. B. Thiermann listed Eastern Kingbirds as cowbird hosts. Lowther (1983) reported added this species to Iowa's list of cowbird hosts. The nest was found on one instance of parasitism in which the cowbird egg was ejected - on 25 June 1981 in Story County. a usual practice of kingbirds (Rothstein 1975) - and the nest Bell's Vireo, Vireo bellii Audubon. -F: 147, "infrequently"; NC: 0 deserted. of 0. Bennett (1917) found 7 of 13 nests parasitized and Rosene Horned Lark, Eremophila alpestris (Linnaeus). - F: 36, 1; NC: 0 of (1941) noted 4 of 5 nests to have cowbird eggs. Stoner (1919) and 2. Savage (1894a:34) noted that he would "often find one or more" Carter (1957a) also recorded Bell's Vireo as a cowbird host.