Foam Lake Birding No. 118


No. 118

This past week I have seen the extensive flooding around Yorkton and Humboldt which brought back not so fond memories of the very wet 1950s - at least where I lived. Then, as now, flooding has caused small isolated bodies of water to swell their banks and flow to other similar bodies of water eventually connecting to lakes and streams that contain fish. As a result the fish end up in all sorts of unlikely places bringing fish eating predators with them, especially birds.

One such group of birds is the family of terns and except for one species, the Black Tern, (see article No. 56) all are primarily fish eaters. With the recent flooding and resultant movement of minnows terns can be found almost anywhere. This is exactly what I came across along a roadside near Waldsea lake just north west of Humboldt where we watched a small flock of black capped white terns feeding.

Just by watching them I could not determine with certainty what species they were because there are two very similar terns in the same area, the Common and Forster's. After taking a large number of photos the pure white wing tips, as seen from above, and the pure white bodies were the field marks that confirmed my suspicions that the birds were the Forster's Terns. In the Common Tern the corresponding parts are grey. Had they been vocal, as terns usually are, identification would have been easy. The Common Tern utters a constant barrage of high pitched scolding calls similar to that of the Black Tern while the Forster's gives a raspy single call repeated leisurely which one birder described as a "croak". These particular birds must have been very hungry as they were absolutely silent .

This week's photo shows three Forster's Terns fishing. One has just spotted a fish and is getting ready to dive; the second is in a dive and is just about to enter the water; the third is in the water and is just starting to emerge. Enjoy!