[NatureNS] Dead murres and "scoping" waterfowl footnote

Date: Sun, 17 Feb 2013 17:53:15 -0400
From: iamclar@dal.ca
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All:

Paul Brodie found a  dead Common Murre floating off Boutlliers Pt.,  
HRM, can be added to the current toll and coastal span.

I thought Nancy Dowd's suggestion, that "scoping" birds might be  
initiating the dive reflex very interesting. But I don't think it  
covers the prolonged scoping one sees among some, but not all, divers.  
The reflex (also occurs in diving mammals, and even people to a  
limited extent), is set very quickly when the face hits the water.

On the other hand, I don't see (do others?) diving ducks like Athyas  
and eiders do much if any scoping, yet mergansers do so. The former  
feed on relatively or completey fixed food (weeds & small inverts.,  
mussels resp.), whereas loons (save the odd crab munchie), alcids and   
mergansers, are piscivores scoping for location-shifting, active prey.

So the question remains, why don't cormorants scope? They can set the  
dive reflex readily enough, as Nancy indicates. Am I missing something?

Cheers, Ian

Ian McLaren

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