264-012-song-sparrow-2005-04-25-damon-s-calderwood-maple-ridge-bc-canada-0001

On 23 April 2005, Don noted a Song Sparrow (Melospiza melodia) carrying a big beakful of insects as it flitted from reed to reed beside the Alouette River in Maple Ridge, British Columbia. We watched the adult fly from one small stalk to another, apparently focused on a patch of brambles. It hopped into the brambles and soon emerged without food, flying to a nearby tree where it wiped its bill. It was a surefire indicator that she had just fed her young.

A short search of the bramble patch revealed a delicate nest of reed stems that contained three young about five days old. The nest was only two feet above the ground, attached firmly to bramble stems, and well hidden among the grasses and reeds. The parents were watched sneaking into the nest with food through the backside of the bramble patch but they always left the site from the left side of the nest.

On 24 April we set up a blind to take some photographs. Don noticed the adults were feeding their young tiny, silvery fish. After observing this a few times, we realized what a unique opportunity we had because we knew from pervious field work that Song Sparrows feed mainly on seeds and insects. The fish were fry of the Chum Salmon (Oncorhynchus keta) which were common in the brackish waters of the Alouette River nearby. We speculated that the Song Sparrows were hunting for them in small pools along the river’s edge as the tide receded. The fry were estimated at 25-30 mm long.
Don set out to follow the Song Sparrows with his binoculars as they foraged along the river. He saw them hopping about small pockets of water quite frequently but never witnessed them catching a fish. Over the next few hours the parent sparrows still continued to feed their nestlings salmon fry. Adults were never observed eating fry.

On 25 April the feathered nestlings were still being fed salmon fry (Figure 1). The inventive Song Sparrows we discovered had found a way to combine opportunity with ingenuity and take advantage of a wonderful food source. It was a tremendously rewarding experience. The only other passerine in our area that is known to feed fish to its young is the American Dipper (Cinclus mexicanus).

http://www.wildlifebc.org/pdfs/4_2_Caldewood_Waite.pdf