Foam Lake Birding No. 116


No. 116

Whenever I think of transient birds my mind usually recalls the various sparrows such as the White Throated, White Crowned, Harris and Lincolns that occur regularly in our backyards and are presently here. However, there are many other transients, waders for example, that never visit our yards but are quite common in rural areas.

This spring I happened to see several different waders and from that group decided to feature the Lesser Yellowlegs. The Lesser Yellowlegs is a smaller version, a twin as it were, of its close relative the Greater Yellowlegs that was covered in Article No. 22. Just about everything that was said about the Greater can also be said about the Lesser.

So, what are the field marks that can be used to tell them apart? In mixed flocks the size difference is very noticeable and can be used with confidence. If the birds are not in mixed flocks, there are two differences that are not too subtle and can be used to determine which is which. First, the distress call of the Lesser, when scared up, is a rather gentle two note yew yew; the distress call of the Greater is a much more pronounced three note dill dill dill. Second, if the birds are silent, bill length can be used with good reliability in much the same manner as is used to distinguish the Downy from the Hairy Woodpecker. (See Article No. 27). The bill of the Lesser is finer, straighter and shorter than the heavier, slightly up- curved and much longer bill of the Greater. The bill length of the Lesser is just slightly greater than the distance from the base of its bill to the back of its head; The bill length of the Greater is almost twice as great as the distance from the base of its bill to the back of its head.

This week's photo was taken this spring near a widely flooded Waldsea Lake just north of Humboldt. The birds in this instance were easy to identify because they were accompanied by the much larger Willet (not in the picture) which is approximately the same size as the Greater Yellowlegs. In the colour photo the yellow legs really stand out immediately identifying it as one of the two species of Yellowlegs.