Turkey Vulture (Cathartes aura) Torrey Wenger
© Tom Hodgson
HU (Click to view a comparison of Atlas I to II)
Few people admit to liking this bald-headed recorded on a December 2007 Winter Feeder Survey report (Kalamazoo Nature Center 2009). scavenger, but the entire state benefits from the The MAS Michigan Bird Survey documents Turkey Vulture's carrion removal services. Turkey Vultures in a dozen or fewer counties Potentially dangerous bacteria that might pass during the winter months, December through unscathed through a mammal or insect February; (Wuepper 2008, Murphy 2005). scavenger are destroyed in the vulture's Christmas Bird Count observers in Michigan digestive tract (Kirk and Mossman 1998). Add have recorded Turkey Vultures sporadically to this its remarkable soaring abilities and since the early 1980s and regularly since the incredible sense of smell and you have a mid-1990s (National Audubon Society, Inc. wonderful – if not beautiful – bird. 2009). These observations imply that Turkey
Vultures are leaving later, wintering further The two species of Cathartid vultures, turkey north than they have historically, and returning and black, can be tough to find in American earlier. field guides. Originally placed with the diurnal raptors, they were grouped with the storks in The bulk of vultures are not “early birds”, 1998 but were moved back in 2006 (Banks et al. however. The Winter Feeder Survey has 2007). Genetic and behavioral similarities are recorded 186 Turkey Vultures in March still being studied to better understand how (Kalamazoo Nature Center 2009). The MAS vultures are related to other birds. The South Seasonal Survey documents vultures in 60 or American checklist avoids these problems by more counties during the spring, March through placing New World vultures in their own order, May (Reinoehl 2004, 2008). Hawk counts at the Cathartiformes (Remsen et al. 2009). Whitefish Point Bird Observatory show an
increased number of vultures, but the arrival Distribution date of March 26 is on par with the 20-year Eastern birds are short-distance migrants average (Brennan 2009). wintering primarily in the southeastern U.S.
(Kirk and Mossman 1998). Typical arrival The Turkey Vulture's northward expansion has dates are in March in the southern counties continued in Michigan. During MBBA I, the (Adams 1979). “Early” vultures show up with vulture was recorded in 53% of townships warm southerly winds – a Turkey Vulture was statewide; during MBBA II, this jumped to
© 2010 Kalamazoo Nature Center Turkey Vulture (Cathartes aura) Torrey Wenger nearly 68%. The largest increase was in the UP encountering vultures more than doubled (Peck where the number of townships with recorded 2007). This is also supported by BBS data at Turkey Vultures tripled. However, the state, regional, and continental levels. While Michigan map needs to be interpreted with Breeding Bird Surveys are not ideal for caution. MBBA protocol classified any Turkey monitoring vultures – who may not begin Vulture flying over a site as “possible” rather foraging until five hours after sunrise, than “observed”. Turkey Vultures nest in depending on wind conditions – they can be isolated areas, forage over miles of territory, and used for density comparisons (Kirk and gather in communal roosts at night (Kirk and Mossman 1998). Throughout Canada and the Mossman 1998). They certainly use two-thirds U.S., Turkey Vultures have shown statistically of the state's townships but it cannot be said significant increases of 1.8% per year from 1966 they nest in all of those townships. Breeding through 2007; in USFWS Region 3 (the Upper was confirmed in only 32 townships, primarily Midwest), they have increased by 6.5% in SLP. This is not surprising considering the annually; and in Michigan, they have increased vulture's secretive nesting habits. No vulture- at 6.5% annually (Sauer et al. 2008). specific studies were carried out during the MBBA II period so most confirmed nests were Common explanations for the northward accidental discoveries. expansion include increased road building and therefore a steady supply of road killed carrion, Breeding Biology a burgeoning deer herd, forest clearing, and Turkey Vultures can be considered “cavity warming trends (Kirk and Mossman 1998). The nesters”, using a wide variety of “dark recesses” road kill theory is generally held to be the most from tumbled boulders to old mammal dens to important (Peck 2007) but does not explain the thick brush (Kirk and Mossman 1998). Nests situation in the UP very well. More study needs are generally spaced well apart in areas isolated to be done. from human disturbance. Two eggs are typically laid and both parents incubate; the Conservation Needs eggs are resistant to chill and may take up to 40 The population is not currently at risk. days to hatch. If the nest is lost, the pair may However, conservation issues do exist. Turkey attempt a second clutch in an alternate location Vultures depend on isolated areas in which to (Kirk and Mossman 1998). The young are fed nest and roost. Deforestation and habitat by regurgitation and will regurgitate as a fragmentation pose obvious risks to this retiring defensive measure. The young begin spending bird. Climate change is already affecting this time outside the nest cavity at 40-60 days and species (Butler 2003). The Black Vulture, a will fly at 60-80 days. Parental dependence is more gregarious but also more aggressive short-lived, and young quickly join the cousin to the Turkey Vulture, reaches the communal roosts (Kirk and Mossman 1998). northern edge of its range at the southern edges of Illinois, Indiana, and Ohio. Should this Abundance and Population Trends species expand into Michigan, it will compete (Click to view trends from the BBS) HU for the same nesting areas and can outcompete The apparent population increase is real and not the Turkey Vulture for food resources (Kirk and an artifact of sampling – the same protocol was Mossman 1998). used for both Atlas efforts. Similar increases are documented in the second Atlas of New Additionally, Turkey Vultures are a concern York where the incidence of Turkey Vultures near airports. U.S. Air Force data show that rose by two-thirds (McGowan 2008) and in the Turkey Vultures account for 31% of their second Atlas of Ontario, where the likelihood of
© 2010 Kalamazoo Nature Center Turkey Vulture (Cathartes aura) Torrey Wenger birdstrike incidents and are most frequently North America, No. 339 (A. Poole and F. encountered during the late summer, after the Gill, eds.). The Birds of North American, young have fledged (Kelly 1999). Another Inc., Philadelphia, PA. report states that while vulture birdstrikes are McGowan, K.J. 2008. Turkey Vulture. In rare – only 1-2% of all U.S.A.F. collisions – McGowan, K.J., and K. Corwin (eds.). 2008. they account for 40% of the dollar damages The Second Atlas of Breeding Birds in New (Speelman et al. 1999). A number of lethal and York State. Cornell University Press, Ithaca, non-lethal control measures are under NY. investigation. Murphy, B. 2005. Michigan Bird Survey: Winter 2004-2005 (December-February). Michigan Birds and Natural History 12: 145-163. National Audubon Society, Inc. 2009. Christmas Bird Count historical results: Literature Cited data for a species.
© 2010 Kalamazoo Nature Center Turkey Vulture (Cathartes aura) Torrey Wenger
Speelman, R.J. III, M.E. Kelly, R.E. McCarty, and J.J. Short. 1999. Coping strategies for the aircraft birdstrike problem: resisting impacts, avoiding collisions, and… Proceedings of the 1999 Bird Strike Committee – USA/Canada, First Joint Annual Meeting, Vancouver, BC. Wuepper, J.T. 2008. Michigan Bird Survey: Winter 2007-2008 (December-February). Michigan Birds and Natural History 15:100- 123. Suggested Citation
Wenger, T. 2010. Turkey Vulture (Cathartes Aura). In Chartier, A.T., J.J. Baldy, and J.M. Brenneman (eds.). 2010. The Second Michigan Breeding Bird Atlas. Kalamazoo Nature Center. Kalamazoo, MI. Accessed online at:
© 2010 Kalamazoo Nature Center