For the past few weeks, neotropical migrants have moved through the forest in waves. They pause for a few days of food and rest, then one fine night they’re up and out. By morning a host of new arrivals is busily feeding in the same trees. A group of hungry Yellow billed Cuckoos arrived last week, allowing me the chance to view up close these usually furtive birds.
In birder parlance, an invasion is an unusually large wave of migrants, usually clustered in one region. The number of cuckoos in this forest certainly didn’t meet that criteria, yet their size and feeding behavior made them quite noticeable. The resident breeding birds noticed too. Judging by the many chases I saw, the robins and cardinals were feeling a bit threatened by these big, hungry newcomers barging into their territories and eating the bugs they needed for their young.
Their very active feeding behavior in the days after arrival taught me some things about Yellow-billed Cuckoos. On hot, humid afternoons their distinctive kuk-kuk-kuk-kowp-kowp-kowp-kowp hoot-like call drifts from high in the canopy, but glimpses of the actual bird have been few. They are described as sluggish, shy and furtive.
But these migrating cuckoos were uncautious – gliding from limb to limb, fluttering to the ground to pluck a choice insect, then perching on a low open limb in plain view to eat it and watch for another.
“Caterpillars top the list of Yellow-Billed Cuckoo prey: individual cuckoos eat thousands of caterpillars per season. On the East coast, periodic outbreaks of tent caterpillars draw cuckoos to the tentlike webs, where they may eat as many as 100 caterpillars at a sitting… They also take advantage of the annual outbreaks of cicadas, katydids, and crickets, and will hop to the ground to chase frogs. (All About Birds: The Cornell Lab)
Their diet makes cuckoos vulnerable to pesticide use. Yellow-billed populations in the west have been in a serious decline for some time, but won’t be afforded protection due to a debate over whether it’s a true subspecies of the more common eastern bird.
These are incredibly handsome birds, a real treat to see at close (binocular) range. Long, pointed wings and tail, big dark eyes, a warm cinnamon hue in their wing feathers – and that amazing beak. Cuckoos can be mistaken for robins if you only see their back. But a front view reveals the white breast and unique white ovals in the under-tail feathers.
A friend of mine saw a Yellow-billed Cuckoo last evening at the edge of the forest, so some of the migrants are still around. The Black-billed Cuckoo, a much rarer bird whose populations are declining, has also been seen here.
I’ve started hearing their calls, which means our resident birds are beginning to nest. It was once believed their calls presaged rain, hence the common name “rain crow”. Likely all I will get of cuckoos for another season is that distant hooting on a hot afternoon – for me it’s the voice of summer.