There are cunning strategies and nefarious practices that some birds use to secure nests or caregivers to their eggs. Are these ploys to ensure survival of their species or just bad mind? Faraaz Abdool looks at some birds that get others to do these jobs.
It’s the start of spring in the temperate northern hemisphere and here in the tropics we’re also undergoing a shift in the seasons. Subtle changes in weather may be imperceptible to humans, but to the trees and animals, the signals are clear. Countless trees in the forest have burst into flower, some are just releasing their seeds, and others are already sprouting new leaves. To coincide with this boon in resources, many birds are also entering their breeding season.
While some species of resident birds in TT do breed all year, there is a marked increase in breeding activity at this time of year. From tanagers to mockingbirds to oropendolas, all are on the critical mission of sourcing a suitable nest location, obtaining the correct materials, construction, copulation, incubation, fending off predators, and finally the tiresome task of feeding and cleaning up after any number of fuzzy baby birds. Well, not exactly everyone. There are a few species of birds within our islands which do not subscribe to the conventional model. They are the birds waiting on the periphery, interested in the goings-on of the aforementioned tanagers, mockingbirds, wrens, oropendolas, and so on. Oftentimes they are chased off by devoted parents. But their success in bringing the next generation into the world depends on persistence and dogged determination to infiltrate the ranks.
[caption id="attachment_947390" align="alignnone" width="1024"] A male giant cowbird engages in a courtship display. - Faraaz Abdool[/caption]
Consider the shiny cowbird. Aptly named, for the males are indeed quite shiny and they do tend to associate with cows. Generally unassuming, they are tanager-sized birds with a stately posture. Sleek, contemplative birds with a sweet song, the males of the species may seem completely black but alternate between glistening green and purple depending on the incident light. Females are a dull, washed-out brown, and they are responsible for selecting a nest. Minor detail here is that this nest she selects belongs to another species.
Shiny cowbirds are observant creatures and can often be seen perched, watching the frenetic nest-building activities of palm tanagers, blue-grey tanagers, tropical mockingbirds, or the endearing house wren. At times these birds would actively chase the cowbirds away from the vicinity of their nest. But the cowbirds would always remain within view. Once a nest has been built and eggs laid, it’s time for the female shiny cowbird to make her move.
The same drama unfolds on a larger scale with the shiny cowbirds close relative, the giant cowbird. Towering over its smaller cousin, the giant cowbird shares many characteristics including its breeding behaviour – officially termed “brood parasitism.” Within the sphere of brood parasitism, the
