A species' ability to deal with Brown-headed Cowbirds depends on the habitat they're in, and whether they've co-evolved with cowbirds or not.  Cowbirds are more grassland/shrub habitat species and so other species in those habitats have evolved ways of identifying and dealing with cowbird nest parasitism.  I think Common Yellowthroats are a species that has been mentioned as being capable of recognizing and dealing with cowbird parasitism.  However, cowbirds are also capable of exploiting edge habitats.  As development has occurred resulting in greater forest habitat fragmentation, which results in increased amounts of edge habitat, Cowbirds have been able to exploit areas where they previously have not had access to.  Additionally it means that forest interior species that have not previously been exposed to cowbird parasitism in great amounts are now more often exposed to them.  These forest interior species (wood thrushes, tanagers, wood warblers, etc.) are the species we think of most often when we hear about the perils of nest parasitism by cowbirds.  Kirtland's Warblers are the poster child of forest species that have experienced major population declines partly due to habitat fragmentation and cowbird nest parasitism.  Forest fragmentation has occurred so rapidly that many forest interior species have not been able to adapt to the increased parasitism.

 

So, depending on what habitat you live in or near may help determine whether your local species are capable of dealing with cowbirds or not.

 

Of course I'm not 100% certain that you've got a cowbird, though it did seem like one from the photos.

 

Good luck!

 

Casey

 

 



	-----Original Message----- 

	From: MU Ornithology Listserv (ZOO 408) on behalf of Debra Bowles 

	Sent: Sun 8/21/2005 10:22 PM 

	To: [log in to unmask] 

	Cc: 

	Subject: Re: help...

	

	



	Anne, why the rehaber you're working with fails to acknowledge parental

	birds' abilities to identify parisitic-species' eggs is a mystery to me. It

	is a documented fact that some birds recognize and remove intruders' eggs.

	Some don't pay any attention to them or at least don't seem to recognize

	them at all and some, as Casey suggested, will build nests right over the

	top of them.

	

	I wonder... if it also varies from bird to bird like, as in humans: "We all

	have our own ways?"

	

	House Wrens will sometimes puncture and/or remove eggs from other birds'

	nests.

	

	Anyway, good luck, and if this tiniest of creatures pulls through thanks to

	your care and concern, consider joining our ranks!

	

	Debra Bowles

	Rehabilitating native birds via

	Second Chance Wildlife: 513 875 3433

	

	

	

	

	

	

	

	

	

	

	

	

	-----Original Message-----

	From: MU Ornithology Listserv (ZOO 408)

	[mailto:[log in to unmask]]On Behalf Of Anne HOOKE

	Sent: Sunday, August 21, 2005 9:40 PM

	To: [log in to unmask]

	Subject: Re: help...

	

	

	Casey, the bird is still alive (mirabile dictu!) and the guy at Second

	Chance has given me feeding instructions if it survives until

	tomorrow...  It is in a home-made incubator right now.  BTW, the guy at

	Second Chance disputes the hypothesis that the nest "owner" recognized

	the alien as an intruder...  But there is absolutely no nest nearby that

	I can spot to account for a fall...  Does anyone want to weigh in on

	this?

	Cheers, AMH

	

	

	>>> "TUCKER, Casey" <[log in to unmask]> 8/21/2005 11:52:04 AM >>>

	Anne,

	

	Contact a local rehabilitator as quickly as possible.  You can find a

	list of local rehabilitators at the following web-site.

	

	http://www.dnr.state.oh.us/wildlife/Resources/orphans/rehabilitators_04.htm

	

	

	In the meantime keep the bird in a warm protected spot (a bowl lined

	with guaze, like that pictured, would work well).

	

	There is a chance this is a cowbird egg/chick (based on the photo) that

	has been evicted by a host species that is capable of differentiating

	between a cowbird and its own eggs.  Some species are capable of

	recognizing when a cowbird has laid an egg in their nest, and will take

	steps to counter the cowbird.  They may achieve this by removing the egg

	entirely and drop it elsewhere.  Other species may just build nest

	material over the parasite's egg and smother it.

	

	Good luck!

	

	Casey

	

	        -----Original Message-----

	        From: MU Ornithology Listserv (ZOO 408) on behalf of Anne HOOKE

	

	        Sent: Sun 8/21/2005 11:42 AM

	        To: [log in to unmask]

	        Cc:

	        Subject: help...

	

	

	

	

	        Here is a photo of the bird trying to get out of the egg...I

	doubt that

	        knowing what kind of bird it is will help with the advice on

	what to

	        do...but I thought it was worth a shot...

	        Cheers, AMH

	

	        Anne Morris Hooke, PhD

	

	        Professor and Chair

	        Department of Microbiology

	        Miami University

	        Oxford, OH  45056

	

	        [log in to unmask]

	         513-529-5422

	         513-529-2431 (fax)

	

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