Here is the song of the Yellow-billed Cuckoo, a simple kow-kow-kow-kow-kow, etc. In an article for Birding Magazine, way back in 2011, not long after I recorded this bird, I proposed that we could divide the singing of North American landbirds into three grades. The Yellow-billed Cuckoo is the poster-bird for Grade 1, whose songs are simple tunes or monotonous series of identical or very similar notes, like this one. Grade 2 belongs to the flycatchers. More on them soon. Grade 3, the pinnacle of song complexity, is exemplified by most of the species we have covered so far, with the Wood Thrush near the pinnacle of both acoustical and syntactical virtuosity. (You can hear one in the background of this recording.) Grade 3 is restricted to the oscines, that portion of the songbird order (Passeriformes) capable of learning new songs. Grade 1 comprises all the nonpasserines except hummingbirds and parrots, and includes some of the suboscine passerines as well. We will probably find an example of that group in Costa Rica next March.
Back to cuckoos, they are a worldwide family (Cuculidae) of rather large and slender, long-tailed birds that are mostly arboreal, although some, such as roadrunners, have adapted to living on the ground. The Squirrel Cuckoo of Costa Rica and Groove-billed Ani of Texas are two representatives of the family that are slated for a later appearance here. The word "cuckoo" is onomatopoeic, but the species that say cuckoo are in the Old World genus Cuculus. Ours don't do that. They also don't lay their eggs in the nests of others, the practice that led to the word "cuckold." But let's be clear, it's a bum rap. Old World cuckoos don't practice cuckoldry, not in the human sense of the word. What they practice is crypto-adoption. Ornithologists call it brood parasitism. In America it's the cowbirds that do this. Not that birds aren't above extra-pair relations with the neighbor's mate; that is widespread. So, many, many species of birds do practice cuckoldry in the human sense, just not the cuckoos. We will work a discussion of that into another day, because singing at dawn is strongly implicated in the consummation of trysts.