Swallow foraging

[Brian A]

Over the last week we have had several species of "Mayflies" hatching at Bear Lake here in Manistee County.

The weather has been quite cold and windy for this time of year and I would suppose creating some hardship for aerial feeders like swallows and swifts.

The Mayflies swarm in tremendous numbers but not usually until dusk.  Last night I was out and saw a mixed flock of Barn, Rough-winged, Bank (unusual away from the cliffs at Lake Michigan) Tree Swallows and Chimney Swifts circling above a wooded hill just downwind of the lake. The mayfly swarms were lower at ground level up to about tree top level with very few at any higher height.

The swallows made no flight lower into this smorgasboard of insects for at least a half hour that I was able to observe.  I was able to fix my binocular view focused at the height of the swallows and saw no mayflies there whereas I could focus at a similar distance horizontally and still see evidence of mayflies.

Does anyone know why there is no apparent sensible feeding by these birds?  I see Cedar Waxwings and Grackles successfully feed on the mayflies as they roost in the day in lakeside vegetation.  Stupid swallows.

Brian Allen
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