[Ontbirds] Evidence of Nest Parasitism, Cardinal and Cowbird - Cranberry Marsh, Whitby

Keith Linton klinton at netrover.com
Mon Jul 22 21:04:59 EDT 2013

If anyone hasn't seen this type of behaviour before, I'm fairly certain that 
the following sighting is repeatable:

At the north trail access on Halls Road for Cranberry Marsh, an adult male 
Cardinal was travelling from tree to tree with a juvenile Brown-headed 
Cowbird in tow, which was begging using what seemed to be the female Cowbird 
chatter-call. The male Cardinal promptly returned with some unknown food 
source and fed the youngster.

At first I was shocked, until I realized that what I was seeing was evidence 
of a successful Cowbird 'egg deployment' in a Cardinal nest! Obviously, 
"daddy" was feeding his young.

The cowbird was brown over all with a lighter, finely streaked chest and 
belly, a light throat and a thick, dark gray beak. It was well developed and 
plumed and was calling with a strange Cardinal-like chip at first. I was 
quite confused by what I was seeing as it sat there "tinking" in the brush. 
As the Cardinal approached, the youngster followed, and the above feeding 
was observed.


Halls Road and Cranberry Marsh can be accessed by exiting the 401 at Brock 
Street in Whitby and heading south a few hundred yards to Victoria Street. 
Head west for about 3 km to Halls Road, where a left turn (south for 1km) 
will take you to several trail access points for Cranberry Marsh. There are 
many Cardinals in evidence, but the bird was in the first (north) trail 

Good luck.

Keith Linton
Orono, ONT.

(If anyone is interested, Grasslands National Park in Saskatchewan has quite 
a few Burrowing Owls that are easy to see, and the bottom corridor of the 
Canadian praries is chock full of Ferruginous Hawks right now. I just return 
from there with my daughter. I can give directions to McCown's Longspur, 
Sprague's Pipit's, a lake full of Avocets...all kinds of fun stuff!)

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