Monday, July 8, 2013

Welcome Swallows again

After my posting last week I got some replies about Welcome Swallows taking prey from below the surface of water. One email was from Mandy King in Warrnambool who sent me photos of swallows feeding in this manner. They were taking prey from a pool in an ephemeral wetland just west of Warrnambool. The photos were taken in the first week of August 2007.
Habitat photo showing clear water and flock of Welcome Swallows hunting and feeding (Mandy King)

Bird centre left is attacking prey and the rest are hovering in wait  (Mandy King)

Bird waiting to attack (Mandy King)

Brian Johnston sent me photos of swallows feeding from the same pool I saw them in at the WTP, Werribee. His photos were taken on 30th June 2012 and mine on 17 July 2012. This means that a food source of insect larvae was available from the pool for more than 2 weeks and that the swallows were feeding on it for at least that long.
Bird capturing prey (Brian Johnston)

Bird with prey doing "head swinging" motion. The prey is clearly visible in the beak (Brian Johnston)

Brian’s photos show the swallow using the same head swinging movement as seen in my photo. Brian suggested that this swing of the head, of nearly 180º, is part of the food capture movement and I agree it may be a method of quickly getting the prey clear of the water. It may also be a method of clearing water from the mouth, or both suggestions may be correct.

What is not know yet is how far the head swing goes. My photo shows the head about 170º to the left (below) while Brian's shows it at about 170º to the right. The question is; after a larvae is captured, is the head swung randomly as to left or right, or does the bird do a full 340º +/- swing of the head? 
Head swung to left (Jenny Spry)

I now have four reports from late June to early August. Two reports are from 2007 and two from 2012. As it is early July swallows should now be feeding in this manner along the Victorian coast, and perhaps elsewhere. Please keep a watch on flocks of swallows in your local patch, and elsewhere.

Brian also has a photo of a Welcome Swallow coming out of the "tail stand luring" position that I mentioned in my blog of swallows using the attenuated tail feathers during hunting.
Swallow moving from "tail stand luring" position to attack (B Johnston)

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