DOCSLIB.ORG

Brown-Headed Cowbird (Molothrus Ater) Doug Powless

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Brown-Headed Cowbird (Molothrus Ater) Doug Powless Brown-headed Cowbird (Molothrus ater) Doug Powless Grandville, Kent Co., MI. 5/4/2008 © John Van Orman (Click to view a comparison of Atlas I to II) Brown-headed Cowbirds likely flourished Distribution Brown-headed Cowbirds breed in grassland, alongside the Pleistocene megafauna that once prairie, and agricultural habitats across southern roamed North America (Rothstein and Peer Canada to Florida, the Gulf of Mexico, and 2005). In modern times, flocks of cowbirds south into central Mexico (Lowther 1993). The followed the great herds of bison across the center of concentration and highest abundance grasslands of the continent, feeding on insects of the cowbird during summer occurs in the kicked up, and depositing their eggs in other Great Plains and Midwestern prairie states birds’ nests along the way. An obligate brood where herds of wild bison and other ungulates parasite, the Brown-headed Cowbird is once roamed (Lowther 1993, Chace et al. 2005). documented leaving eggs in the nests of hundreds of species (Friedmann and Kiff 1985, Wild bison occurred in southern Michigan and Lowther 1993). The evolution of this breeding across forest openings in the East until about strategy is one of the most fascinating aspects of 1800 before being hunted to near-extinction North American ornithology (Lanyon 1992, across the continent (Baker 1983, Kurta 1995). Winfree 1999, Rothstein et al. 2002), but the Flocks of cowbirds likely also inhabited the cowbird has long drawn disdain. Chapman prairies and woodland openings of southern (1927) called it “. a thoroughly contemptible Michigan prior to the 1800s (Walkinshaw creature, lacking in every moral and maternal 1991). Brewer (1991) points out that cowbirds instinct,. ” Martin et al. (1961) wrote: were on Sager’s Michigan bird list of 1839. In “Apparently this social parasite is either too lazy contrast, cowbirds were not noted in Ontario or too smart to take care of its own domestic until the 1870s (Falk 2007). duties.” Although ornithologists today are concerned about the effects of cowbirds on Cowbirds likely did not spread farther north in other birds (Robinson et al. 1995, Rosenberg et Michigan until after logging and subsequent al. 1999), current views are not so scornful, and wildfires of the late 1800s (Mayfield 1961a). some consider cowbirds “a fascinating study in The southern LP was logged and farmed by behavior” and “marvelous to watch” (Stokes 1870, but the northern LP and UP were still and Stokes 1983). more than 90% forested then (see map from © 2011 Kalamazoo Nature Center Brown-headed Cowbird (Molothrus ater) Doug Powless Whitney 1994 in Askins 2000, pg. 79). But takes hosts’ eggs and young from the nest soon, logging, agriculture, and large scale (Mayfield 1961a, 1961b, Payne 1965, Lowther wildfires swept across the state and reduced 1993, Elliott 1999). The mating system might forest cover in large areas (Dickmann and vary from monogamy, to polygyny, to Leefers 2003), thus enabling cowbirds to reach promiscuity depending on habitat, sparsity of as far north as the NELP by the 1880s (Mayfield host nests, and sex ratios (Teather and 1961a, 1993). Wood and Frothingham (1905) Robertson 1986). found cowbirds in Oscoda and Crawford Counties during their 1903 quest for birds along Abundance and Population Trends the Au Sable River, but did not comment on (Click to view trends from the BBS) them. Cowbirds were recorded in the NWLP Survey data show Brown-headed Cowbird around Douglas Lake by 1910 (Pettingill 1974). population declines at all landscape scales. Data Wood (1918) also found cowbirds in the early from Berrien County showed declines from the 1900s as far north as northwestern Alger Co. in mid-1970s to 1991 (Booth 1994). Michigan the UP, but he only noted their presence, an BBS routes show a statistically significant indication that he was not surprised to find decline of 1.95% from 1983-2007 (Sauer et al. cowbirds that far north by then. 2008). Regionally, the BBS data also show a slight, but steady and significant annual decline Today, the cowbird is a common summer of 0.55% during the same period. It also resident throughout Michigan. There was no declined across North America 1% per year on apparent change in distribution of the cowbird BBS routes from 1966-1996 (Sauer et al. 2008). since the first atlas. A few areas of Michigan These declines appear corroborated by atlas had no cowbirds during both atlas surveys, data—breeding was confirmed in fewer particularly parts of Lake Superior State Forest townships during MBBA II. However, the in northern Luce County and northwestern number of townships with cowbirds in the SLP Chippewa County, the coast of Gogebic County, was similar between atlases, whereas the parts of Ottawa National Forest in western Iron number of townships with cowbirds decreased County, and in Copper Country and Escanaba within the UP and NLP from MBBA I to River State Forests in northeastern Dickinson MBBA II. This decrease in the UP and NLP County and Marquette County. Most cowbirds seems especially indicative of a reduction in migrate to the south each autumn, but some can cowbird habitat in the north since observer be found in southern Michigan through the effort in those regions was greater during winter. MBBA II. Cowbirds also declined in Ontario between atlas periods (early 1980s to early Breeding Biology 2000s) along Ontario BBS routes (Falk 2007). While some other species in North America, These declines might be due to regrowth of such as the Redhead, sometimes lay eggs in forests in the north. other birds’ nests, the Brown-headed Cowbird is an obligate brood parasite—with no ability to A cowbird was first reported during a Michigan build a nest, the female must lay her eggs in the Christmas Bird Count in 1938, but not again nests of other birds, particularly species that nest until 1953 after which they were seen every low in shrubby, young forest, forest edge, and winter (NAS 2009). The number observed open habitats (Lowther 1993). A female peaked during 1988 CBCs in Michigan, but has cowbird can lay no more than one egg per declined in the past 10 years on Michigan day—usually at dawn—but can lay several counts and across the continent (NAS 2009). dozen over a breeding season, and sometimes Cornell’s Project FeederWatch shows a slightly © 2011 Kalamazoo Nature Center Brown-headed Cowbird (Molothrus ater) Doug Powless declining trend in winter in the Great Lakes warbler population growth was limited solely by region over the past 20 years (PFW 2009). amount of suitable habitat (Rothstein and Peer 2005); but most contend that a combination of Conservation Needs intensive habitat management along with Brown-headed Cowbirds have been found to lay cowbird control saved the Kirtland’s Warbler eggs in nests of over 220 species (Lowther (Kelly and De Capita 1982, Walkinshaw 1983, 1993) including some of the rarest warblers in Mayfield 1993, USFWS 2008). As the warbler our region, such as Prairie (Nolan 1978), reaches recovery goals, baseline data on warbler Kirtland’s (Mayfield 1961a, 1992), Golden- productivity and brood parasitism with and winged (Coker and Confer 1990), Hooded without cowbird control will likely be (Ogden and Stutchbury 1994), and, to a lesser important. In the meantime, cowbird control is degree, Cerulean (Rogers 2006). However, a still recommended (Mayfield 1992, Olson 2002, recent review of brood parasitism by the Wells 2007). Prior to cowbird control, National Audubon Society reports that cowbirds Kirtland’s Warbler hosted over 90% of cowbird do not appear responsible for rangewide eggs laid in the area (Walkinshaw 1983). declines of various songbirds, with the Interestingly, De Groot and Smith (2001) have exception of some rare species (Muehter, no shown that cowbirds have no community-wide date given). Since MBBA I, ornithologists have impacts on other songbirds in the jack pine published extensively on the effects of forests of Michigan. landscape factors on songbird productivity and brood parasitism (Askins 2000). Several studies Literature Cited indicate that the songbirds most vulnerable to cowbirds build open cup nests in open and edge Askins, R.A. 2000. Restoring North America’s habitats, but forest-nesting species, such as Birds: lessons from landscape ecology. 2nd Wood Thrush, can also be very vulnerable in Edition. Yale University Press, New Haven agricultural landscapes where forests are & London. 332 pgs. fragmented (Robinson et al. 1995, Trine 1998, Baker, R.H. 1983. Michigan Mammals. Fauth 2000, Ford et al. 2001; but see Fauth Michigan State University Press, East 2001, Knutson et al. 2004) and brood parasitism Lansing, Mich. can increase near patches of agriculture even in Booth, W. 1994. Numerical changes in the forested landscapes (Rodewald and Yahner nesting birds in Berrien County, mid-1970s 2001). Rodewald (2009) also shows that to early 1990s. Michigan Birds and Natural habitat-altering invasive shrubs associated with History 1(1): 10-15. urbanization can promote brood parasitism on a Brewer, R. 1991. Original avifauna and forest bird such as the Acadian Flycatcher. postsettlement changes. In Brewer, R., G.A. McPeek, and R.J. Adams, Jr. (eds.). 1991. In Michigan, the cowbird is infamous as one of The Atlas of Breeding Birds of Michigan. the main threats to the Kirtland’s Warbler Michigan State University Press, East (Mayfield 1960, 1963, 1977, 1992, Radtke and Lansing, Mich. Byelich 1963, Ryel 1981, Walkinshaw 1983, Chace, J.F., C. Farmer, R. Winfree, D.R. 1991, USFWS 2008). The severe effect of Curson, W.E. Jensen, C.B. Goguen, and brood parasitism on Kirtland’s Warbler S.K. Robinson. 2005. Cowbird (Molothrus necessitated the nation’s first cowbird control spp.) ecology: a review of factors program in 1972, and tens of thousands of influencing distribution and abundance of cowbirds have been trapped since (Kelly and De cowbirds across spatial scales.
Load more

Recommended publications
  • The Journal of the Ontario Field Ornithologists Volume 13 Number 3 December 1995 Ontario Field Ornithologists
    The Journal of the Ontario Field Ornithologists Volume 13 Number 3 December 1995 Ontario Field Ornithologists Ontario Field Ornithologists is an organization dedicated to the study of birdlife in Ontario. It was formed to unify the ever-growing numbers of field ornithologists (birders/birdwatchers) across the province and to provide a forum for the exchange of ideas and information among its members. The Ontario Field Ornithologists officially oversees the activities of the Ontario Bird Records Committee (OBRC), publishes a newsletter (OFO News) and a journal (Ontario Birds), hosts field trips throughout Ontario and holds an Annual General Meeting in the autumn. Current President: Jean Iron, 9 Lichen Place, Don Mills, Ontario M3A 1X3 (416) 445-9297 (e-mail: [email protected]). All persons interested in bird study, regardless of their level of expertise, are invited to become members of the Ontario Field Ornithologists. Membership rates can be obtained from the address below. All members receive Ontario Birds and OFO News. Please send membership inquiries to: Ontario Field Ornithologists, Box 62014, Burlington Mall Postal Outlet, Burlington, Ontario L7R 4K2. Ontario Birds Editors: Bill Crins, Ron Pittaway, Ron Tozer Editorial Assistance: Jean Iron, Nancy Checko Art Consultant: Chris Kerrigan Design/Production: Centennial Printers (Peterborough) Ltd. The aim of Ontario Birds is to provide a vehicle for documentation of the birds of Ontario. We encourage the submission of full length articles and short notes on the status, distribution, identification, and behaviour of birds in Ontario, as well as location guides to significant Ontario b!rdwatching areas, book reviews, and similar material of interest on Ontario birds.
    [Show full text]
  • American Redstarts
    San Antonio Audubon Society May/June 2021 Newsletter American Redstarts By Mike Scully At the time of this writing (early April), the glorious annual spring migration of songbirds through our area is picking up. Every spring I keep a special eye out for one of my favorite migrants, the American Redstart (Setophaga ruticilla). These beautiful warblers flutter actively through the foliage, tail spread, wings drooped, older males clad in black and orange, females and second year males in shades of gray, olive green and yellow. For years, the American Redstart was the only species remaining in the genus Setophaga, until a comprehensive genetic analysis of the Family Parulidae resulted in this genus being grouped with more than 32 species formerly placed in the genus Dendroica and Wilsonia. The name Setophaga was applied to the whole by virtue of seniority. Though now grouped in a large genus, the American Redstart remains an outlier, possessing proportionately large wings, a long tail, and prominent rictal bristles at the base of the relatively wide flat beak, all adaptations to a flycatching mode of foraging. Relatively heavy thigh musculature and long central front toes are apparently adaptations to springing into the air after flying insects. The foraging strategy of redstarts differs from that of typical flycatchers. Redstarts employ a more warbler-like maneuver, actively moving through the foliage, making typically short sallies after flying insect prey, and opportunistically gleaning insects from twigs and leaves while hovering or perched. The wings are frequently drooped and the colorful tail spread wide in order to flush insect prey.
    [Show full text]
  • Birds of the East Texas Baptist University Campus with Birds Observed Off-Campus During BIOL3400 Field Course
    Birds of the East Texas Baptist University Campus with birds observed off-campus during BIOL3400 Field course Photo Credit: Talton Cooper Species Descriptions and Photos by students of BIOL3400 Edited by Troy A. Ladine Photo Credit: Kenneth Anding Links to Tables, Figures, and Species accounts for birds observed during May-term course or winter bird counts. Figure 1. Location of Environmental Studies Area Table. 1. Number of species and number of days observing birds during the field course from 2005 to 2016 and annual statistics. Table 2. Compilation of species observed during May 2005 - 2016 on campus and off-campus. Table 3. Number of days, by year, species have been observed on the campus of ETBU. Table 4. Number of days, by year, species have been observed during the off-campus trips. Table 5. Number of days, by year, species have been observed during a winter count of birds on the Environmental Studies Area of ETBU. Table 6. Species observed from 1 September to 1 October 2009 on the Environmental Studies Area of ETBU. Alphabetical Listing of Birds with authors of accounts and photographers . A Acadian Flycatcher B Anhinga B Belted Kingfisher Alder Flycatcher Bald Eagle Travis W. Sammons American Bittern Shane Kelehan Bewick's Wren Lynlea Hansen Rusty Collier Black Phoebe American Coot Leslie Fletcher Black-throated Blue Warbler Jordan Bartlett Jovana Nieto Jacob Stone American Crow Baltimore Oriole Black Vulture Zane Gruznina Pete Fitzsimmons Jeremy Alexander Darius Roberts George Plumlee Blair Brown Rachel Hastie Janae Wineland Brent Lewis American Goldfinch Barn Swallow Keely Schlabs Kathleen Santanello Katy Gifford Black-and-white Warbler Matthew Armendarez Jordan Brewer Sheridan A.
    [Show full text]
  • Threat of Climate Change on a Songbird Population Through Its Impacts on Breeding
    LETTERS https://doi.org/10.1038/s41558-018-0232-8 Threat of climate change on a songbird population through its impacts on breeding Thomas W. Bonnot 1*, W. Andrew Cox2, Frank R. Thompson3 and Joshua J. Millspaugh4 Understanding global change processes that threaten spe- directly (and indirectly) affects the demographic parameters that cies viability is critical for assessing vulnerability and decid- drive population growth. For example, vulnerability in key species ing on appropriate conservation actions1. Here we combine traits such as physiological tolerances and diets and habitat can lead individual-based2 and metapopulation models to estimate to altered demographics11. For many birds, population persistence is the effects of climate change on annual breeding productivity sensitive to the rates at which young are produced, which can change and population viability up to 2100 of a common forest song- as a function of temperature3,12. In the Midwestern USA, greater bird, the Acadian flycatcher (Empidonax virescens), across the daily temperatures can reduce nest survival and overall productiv- Central Hardwoods ecoregion, a 39.5-million-hectare area of ity for forest-dwelling songbirds3, probably because of increased temperate and broadleaf forests in the USA. Our approach predation from snakes and potentially other predators13–15. Studies integrates local-scale, individual breeding productivity, esti- such as these provide a better mechanistic understanding of how mated from empirically derived demographic parameters climate change may alter the key demographic rates that contribute that vary with landscape and climatic factors (such as forest to population growth, but scaling up to estimate population-level cover, daily temperature)3, into a dynamic-landscape meta- responses requires a quantitative approach that integrates climate population model4 that projects growth of the regional popu- and habitat on a broader scale.
    [Show full text]
  • Prairie Ridge Species Checklist 2018
    Prairie Ridge Species Checklist Genus species Common Name Snails Philomycus carolinianus Carolina Mantleslug Gastrocopta contracta Bottleneck Snaggletooth Glyphalinia wheatleyi Bright Glyph Triodopsis hopetonensis Magnolia Threetooth Triodopsis juxtidens Atlantic Threetooth Triodopsis fallax Mimic Threetooth Ventridens cerinoideus Wax Dome Ventridens gularis Throaty Dome Anguispira fergusoni Tiger Snail Zonitoides arboreus Quick Gloss Deroceras reticulatum Gray Garden Slug Mesodon thyroidus White-lip Globe Slug Stenotrema stenotrema Inland Stiltmouth Melanoides tuberculatus Red-rim Melania Spiders Argiope aurantia Garden Spider Peucetia viridans Green Lynx Spider Phidippus putnami Jumping Spider Phidippus audax Jumping Spider Phidippus otiosus Jumping Spider Centipedes Hemiscolopendra marginata Scolopocryptops sexspinosus Scutigera coleoptrata Geophilomorpha Millipedes Pseudopolydesmus serratus Narceus americanus Oxidus gracilis Greenhouse Millipede Polydesmidae Crayfishes Cambarus “acuminatus complex” (= “species C”) Cambarus (Depressicambarus) latimanus Cambarus (Puncticambarus) (="species C) Damselflies Calopteryx maculata Ebony Jewelwing Lestes australis Southern Spreadwing Lestes rectangularis Slender Spreadwing Lestes vigilax Swamp Spreadwing Lestes inaequalis Elegant Spreadwing Enallagma doubledayi Atlantic Bluet Enallagma civile Familiar Bluet Enallagma aspersum Azure Bluet Enallagma exsulans Stream Bluet Enallegma signatum Orange Bluet Ischnura verticalis Eastern Forktail Ischnura posita Fragile Forktail Ischnura hastata Citrine
    [Show full text]
  • Designing Suburban Greenways to Provide Habitat for Forest-Breeding Birds
    Landscape and Urban Planning 80 (2007) 153–164 Designing suburban greenways to provide habitat for forest-breeding birds Jamie Mason 1, Christopher Moorman ∗, George Hess, Kristen Sinclair 2 Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC 27695, USA Received 6 March 2006; received in revised form 25 May 2006; accepted 10 July 2006 Available online 22 August 2006 Abstract Appropriately designed, greenways may provide habitat for neotropical migrants, insectivores, and forest-interior specialist birds that decrease in diversity and abundance as a result of suburban development. We investigated the effects of width of the forested corridor containing a greenway, adjacent land use and cover, and the composition and vegetation structure within the greenway on breeding bird abundance and community composition in suburban greenways in Raleigh and Cary, North Carolina, USA. Using 50 m fixed-radius point counts, we surveyed breeding bird communities for 2 years at 34 study sites, located at the center of 300-m-long greenway segments. Percent coverage of managed area within the greenway, such as trail and other mowed or maintained surfaces, was a predictor for all development- sensitive bird groupings. Abundance and richness of development-sensitive species were lowest in greenway segments containing more managed area. Richness and abundance of development-sensitive species also decreased as percent cover of pavement and bare earth adjacent to greenways increased. Urban adaptors and edge-dwelling birds, such as Mourning Dove, House Wren, House Finch, and European Starling, were most common in greenways less than 100 m wide. Conversely, forest-interior species were not recorded in greenways narrower than 50 m.
    [Show full text]
  • Rejection Behavior by Common Cuckoo Hosts Towards Artificial Brood Parasite Eggs
    REJECTION BEHAVIOR BY COMMON CUCKOO HOSTS TOWARDS ARTIFICIAL BROOD PARASITE EGGS ARNE MOKSNES, EIVIN ROSKAFT, AND ANDERS T. BRAA Departmentof Zoology,University of Trondheim,N-7055 Dragvoll,Norway ABSTRACT.--Westudied the rejectionbehavior shown by differentNorwegian cuckoo hosts towardsartificial CommonCuckoo (Cuculus canorus) eggs. The hostswith the largestbills were graspejectors, those with medium-sizedbills were mostlypuncture ejectors, while those with the smallestbills generally desertedtheir nestswhen parasitizedexperimentally with an artificial egg. There were a few exceptionsto this general rule. Becausethe Common Cuckooand Brown-headedCowbird (Molothrus ater) lay eggsthat aresimilar in shape,volume, and eggshellthickness, and they parasitizenests of similarly sizedhost species,we support the punctureresistance hypothesis proposed to explain the adaptivevalue (or evolution)of strengthin cowbirdeggs. The primary assumptionand predictionof this hypothesisare that somehosts have bills too small to graspparasitic eggs and thereforemust puncture-eject them,and that smallerhosts do notadopt ejection behavior because of the heavycost involved in puncture-ejectingthe thick-shelledparasitic egg. We comparedour resultswith thosefor North AmericanBrown-headed Cowbird hosts and we found a significantlyhigher propor- tion of rejectersamong CommonCuckoo hosts with graspindices (i.e. bill length x bill breadth)of <200 mm2. Cuckoo hosts ejected parasitic eggs rather than acceptthem as cowbird hostsdid. Amongthe CommonCuckoo hosts, the costof acceptinga parasiticegg probably alwaysexceeds that of rejectionbecause cuckoo nestlings typically eject all hosteggs or nestlingsshortly after they hatch.Received 25 February1990, accepted 23 October1990. THEEGGS of many brood parasiteshave thick- nestseither by grasping the eggs or by punc- er shells than the eggs of other bird speciesof turing the eggs before removal. Rohwer and similar size (Lack 1968,Spaw and Rohwer 1987).
    [Show full text]
  • Common Name Scientific Name Acadian Flycatcher Empidonax Virescens American Black Duck Anas Rubripes American Coot Fulica Americ
    Birds of Seven Islands Wildlife Refuge Common Name Scientific Name Acadian Flycatcher Empidonax virescens American Black Duck Anas rubripes American Coot Fulica americana American Crow Corvus brachyrhynchos American Goldfinch Spinus tristis American Kestrel Falco sparverius American Pipit Athus rubescens American Redstart Setophaga ruticilla American Robin Turdus migratorius American Wigeon Anas americana American Woodcock Scolopax minor Bald Eagle Haliaeetus leucocephalus Baltimore Oriole Icterus galbula Bank Swallow Riparia riparia Barn Owl Tyto alba Barn Swallow Hirundo rustica Barred Owl Strix varia Bay-breasted Warbler Setophaga castanea Belted Kingfisher Megaceryle alcyon Black and White Warbler Mniotilta varia Black Vulture Cathartes atratus Black-Crowned Night Heron Nycticorax nycticorax Blackpoll Warbler Setophaga striata Black-Throated Green Warbler Setophaga virens Blackburnian Warbler Dendroica fusca Blue Grosbeak Passerina caerulea Blue Jay Cyanocitta cristata Blue-Gray Gnatcatcher Polioptila caerulea Blue-headed Vireo Vireo solitarius Blue-winged Teal Anas discors Blue-winged Warbler Vermivora cyanoptera Bobolink Dolichonyx oryzivorus Bonaparte's Gull Chroicoephalus philadephia Broad-winged Hawk Buteo platypterus Brown Creeper Certhia americana Brown Thrasher Toxostoma rufum Brown-Headed Cowbird Molothrus ater Canada Goose Branta canadensis Canada Warbler Carellina canadensis Carolina Chickadee Poecile carolinensis Carolina Wren Thryothorus ludovicianus Cape May Warbler Dendroica tigrina Cedar Waxwing Bombycilla cedrorum
    [Show full text]
  • Ecology, Morphology, and Behavior in the New World Wood Warblers
    Ecology, Morphology, and Behavior in the New World Wood Warblers A dissertation presented to the faculty of the College of Arts and Sciences of Ohio University In partial fulfillment of the requirements for the degree Doctor of Philosophy Brandan L. Gray August 2019 © 2019 Brandan L. Gray. All Rights Reserved. 2 This dissertation titled Ecology, Morphology, and Behavior in the New World Wood Warblers by BRANDAN L. GRAY has been approved for the Department of Biological Sciences and the College of Arts and Sciences by Donald B. Miles Professor of Biological Sciences Florenz Plassmann Dean, College of Arts and Sciences 3 ABSTRACT GRAY, BRANDAN L., Ph.D., August 2019, Biological Sciences Ecology, Morphology, and Behavior in the New World Wood Warblers Director of Dissertation: Donald B. Miles In a rapidly changing world, species are faced with habitat alteration, changing climate and weather patterns, changing community interactions, novel resources, novel dangers, and a host of other natural and anthropogenic challenges. Conservationists endeavor to understand how changing ecology will impact local populations and local communities so efforts and funds can be allocated to those taxa/ecosystems exhibiting the greatest need. Ecological morphological and functional morphological research form the foundation of our understanding of selection-driven morphological evolution. Studies which identify and describe ecomorphological or functional morphological relationships will improve our fundamental understanding of how taxa respond to ecological selective pressures and will improve our ability to identify and conserve those aspects of nature unable to cope with rapid change. The New World wood warblers (family Parulidae) exhibit extensive taxonomic, behavioral, ecological, and morphological variation.
    [Show full text]
  • Wood Warblers Wildlife Note
    hooded warbler 47. Wood Warblers Like jewels strewn through the woods, Pennsylvania’s native warblers appear in early spring, the males arrayed in gleaming colors. Twenty-seven warbler species breed commonly in Pennsylvania, another four are rare breeders, and seven migrate through Penn’s Woods headed for breeding grounds farther north. In central Pennsylvania, the first species begin arriving in late March and early April. Louisiana waterthrush (Parkesia motacilla) and black and white warbler (Mniotilta varia) are among the earliest. The great mass of warblers passes through around mid-May, and then the migration trickles off until it ends in late May by which time the trees have leafed out, making it tough to spot canopy-dwelling species. In southern Pennsylvania, look for the migration to begin and end a few days to a week earlier; in northern Pennsylvania, it is somewhat later. As summer progresses and males stop singing on territory, warblers appear less often, making the onset of fall migration difficult to detect. Some species begin moving south as early as mid and late July. In August the majority specific habitat types and show a preference for specific of warblers start moving south again, with migration characteristics within a breeding habitat. They forage from peaking in September and ending in October, although ground level to the treetops and eat mainly small insects stragglers may still come through into November. But by and insect larvae plus a few fruits; some warblers take now most species have molted into cryptic shades of olive flower nectar. When several species inhabit the same area, and brown: the “confusing fall warblers” of field guides.
    [Show full text]
  • FLORIDA FIELD NATURALIST a Fledgling Brown-Headed Cowbird
    FLORIDA FIELD NATURALIST NOTES A fledgling Brown-headed Cowbird specimen from Pinellas County.-First evi- dences of breeding in Florida by the Brown-headed Cowbird (Molothms ater) were in 1956 and 19.57 near Pensacola (Sprunt 1963, Weston 1965). Since then the species has become a common breeder throughout northern Florida and now is spreading rapidly southward in the peninsula. Here \I-e repo~tfirst evidence of breeding in Pinellas County, halfway down Florida peninsula, and describe Tampa Bay area population increases of the species during recent summers. A young fledgling Brox-n-headed Cowbird was brought to the Suncoast Seabird Sanctuary in Pinellas County on 2 June 198.5. It died the same day. Precise locality data were not kept, but little doubt exists the bird was obtained locally. Rarely are birds brought to the sanctuary from outside the county, and for these more precise locality data are kept. The specimen, a female (ovary 3..5 X 3mm, not granular), weighed only 17.5 grams. It is preserved as a study skin (GEW 5736) at the University of South Florida. The primaries and rectrices have remnants of sheaths and the tail (.56.5 mm total length) is about 10 mm shorter than average for adult females. Cowbirds typically weigh about 30 grams at fledging (Mayfield 1960). The incomplete feather growth and light weight support a local origin for the bird. The Nesting Season reports in American Birds and its predecessor Audubon Field Notes provide a good account of the expansion of the Brown-headed Cowbird's breeding range in Florida.
    [Show full text]
  • Chapter 6 Appendices
    Chapter 6 Climate Change APPENDICES 2015-2025 Maryland State Wildlife Action Plan Chapter 6 Appendices 6a. Results of Maryland’s Climate Change Vulnerability Assessment for 265 Species of Greatest Conservation Need 6b. Results of Maryland’s Climate Change Vulnerability Assessment for Globally Rare Plants 6c. Climate Change Tree Atlas Adaptability Rankings for High Reliability Tree Models, Many of Which Occur in Maryland 6d. Documentation of the Climate Change Effects on Maryland Invasive Species Council List of Selected Invasive Species of Concern in Maryland 6e. Predictions of Species-Specific Habitat Shift Due to Climate Change in the Northeast 2015-2025 Maryland State Wildlife Action Plan Appendix 6a. Results of Maryland’s Climate Change Vulnerability Assessment for 265 Species of Greatest Conservation Need Climate Change Status Common Name Scientific Name Vulnerability Index Group1 (CCVI) Flatworms A planarian Paraplanaria dactyligera B Extremely Vulnerable A planarian Phagocata dissimilis sp. nov. A Moderately Vulnerable A planarian Phagocata projecta sp. nov. A Insufficient Evidence A planarian Phagocata virilis A Extremely Vulnerable A planarian Procotyla typhlops A Extremely Vulnerable A planarian Sphalloplana buchanani A Insufficient Evidence A planarian Sphalloplana cava sp. nov. A Insufficient Evidence A planarian Sphalloplana pricei A Insufficient Evidence A planarian Sphalloplana sp 1 A Extremely Vulnerable Hoffmaster's cave planarian Sphalloplana hoffmasteri A Moderately Vulnerable Freshwater Mussels Atlantic spike Elliptio
    [Show full text]