If I say "cuckoo" what word comes to mind?
Yes, clock. One of the world's most interesting bird families is tied to my grandmother's mantelpiece.
If German clockmakers in the early 18th century had been successful in their first desire — a rooster popping out of that little door and crowing on the hour — there would be no "coo-coo" clocks. The clockmakers could not replicate the crowing sound.
Cuckoos are named for the sound they make. This is an example of onomatopoeia — the dictionary definition being: a word created from the sound associated with what is named.
The equivalent of "coo-coo" exists in at least 19 languages as name for the bird, according to Mark Cocker, author of the book "Birds and People." In English, cuckoo is the bird, but also a person regarded as crazy.
Local species
There are 144 species of cuckoos worldwide, two of which can be found in Minnesota: black-billed and yellow-billed cuckoos.
Cuckoos are known for laying eggs in the nests of other bird species. Of the 144 species, 57 are obligate nest parasites — obliged by nature to behave that way.
The two species found here build nests and tend their own eggs and hatchlings unless there is a bountiful food supply. In that case, the hen will continue to lay, searching for nests of other bird species in which to make a deposit.
In Minnesota, possible hosts would include robins, catbirds, cardinals and a few warbler and sparrow species.
Like most cuckoos, our two are shy and secretive, much easier to hear than see, and not that easy to hear. They are birds of forest edges, thickets and second-growth woods. The well-hidden nests are made of twigs and grasses.
My interest in this bird family came from the book "Cuckoo" written by Englishman Nick Davies (available in the Hennepin County Library). He writes mostly about the common cuckoo, a species found from England to the eastern edge of Russia.
A traitor in the nest
This bird is an obligate nest parasite of consummate deception. There are different "races" of this cuckoo, each exclusively using the nest of a specific species. These cuckoos have evolved to lay eggs that very closely match in size and color those of the chosen host.
Our cuckoos choose hosts with eggs that more or less resemble the cuckoo eggs. They have not evolved exactitude.
There is an ongoing battle between cuckoos and hosts to either better disguise the eggs or better recognize them.
If found, the host bird will remove the cuckoo egg from its nest or abandon the nest and begin again. If a common cuckoo egg is unnoticed and hatched, the host can kiss its babies goodbye.
Common cuckoo chicks, early hatchers, blind and naked, just hours from the egg, instinctively remove from the nest the host eggs or hatchlings. The cuckoo chick has a slightly concave area on its back. It uses this characteristic to manipulate and push eggs or baby birds out of the nest.
Aristotle speculated on this behavior. No one believed him. Cocker writes that it took 2,135 years before a scientist observed this practice and offered for scientific publication a paper describing it. The man was Edward Jenner, famed more so for smallpox vaccination.
His paper was initially rejected because the publisher thought Jenner described something that simply could not be.
You might say the publisher thought Jenner was, uh, cuckoo.
Read Jim Williams' birding blog at startribune.com/lifestyle/homegarden/blogs/Wingnut.html.
