Tag Archives: cowbird imprinting

This time of year, there are still large flocks of birds gathering together making the journey southward.
Here in central NC, one such species is the Brown headed Cowbird. I spotted this one (along with a few hundred of his friends) along Mid Pines Rd. in Raleigh yesterday morning.

Though many people dislike Brown headed Cowbirds for their parasitic nesting habits, they are an interesting species nonetheless.
Though they appear black in color (aside from their brown heads), males are actually covered in an iridescent green, blue and deep purple plumage which changes color depending on the angle of light shining down on them.

These beautiful colors may serve an important purpose in the breeding habits of the Cowbird.
Studies have shown that there is a direct correlation between the intensity of hue and saturation of the males iridescent plumage in relation to his overall health.
Cowbirds who were nutritionally deficient produced a greater percentage of dull feathers when molting, while males who were fed a healthy diet with unlimited access to nutrient rich food sources, produced the expected amount of rich colors in their plumage.

It is hypothesized that female birds may possibly interpret the brightness of the males colorful feathers as a signal of a healthy mate.
Although I’m not aware of a specific study which definitely proves this, it would seem reasonable to conclude that the Cowbird with the brightest plumage would have the best luck with the ladies, thus able to pass their genes on to the next generation.

Love them or hate them, IMO they are gorgeous birds, especially when they’re seen in good lighting.

Btw, check out the lone European Starling taking a bath with the flock in the third and fourth pics. He seems perfectly content to hang out with the Cowbirds doing his own thing 🙂

Photos by @sally_siko of @birdwatching_nc on the fabulous full frame @canonusa
#5Ds

Field Notes, Out There with the Expert, The Adventures of your bird watching Admin

Learning how to cowbird

August 13, 2019 admin

Since Cowbirds are known for laying their eggs in the nests of other birds, the question is how does a Cowbird learn how to be a Cowbird instead of a Warbler, Gnatcatcher, or Blackbird host?
Researchers at the University of Illinois observed that the Cowbirds mother actually remained in the host birds territory and could hear the cries of her offspring.
In response to hearing the begging cries of the baby cowbird, the females responded, not by feeding it, but by calling to it.
The researchers think that this behavior may help the cowbird fledglings to eventually find other adult cowbirds that are vocalizing, as they fly from feeding areas to roosting areas at dusk each day.
Nature is endlessly surprising!
Photo by Sally Adams Siko
Canon 5DS
Harris Lake Park, New Hill North Carolina

Field Notes, Out There with the Expert, The Adventures of your bird watching Admin

How cowbird chicks avoid imprinting on their hosts

August 12, 2019 admin

Cowbirds are well known to lay their eggs in the nests of other birds, leaving the young to be raised by other species.
So how do Cowbird chicks avoid imprinting on their host families of Gnatcatchers, Warblers or Blackbirds yet still learn how to be a Cowbird?

A study by the University of Illinois was launched to answer this question. Researchers tracked juvenile cowbirds that were being raised by Prothonotary warblers. They’ve discovered that, at around 30 days old, cowbird fledglings started to leave the warblers’ territory at dusk to roost alone.
They would then return the following morning to be fed by their foster parents. For reasons that aren’t yet clear, these nocturnal departures seem to prevent the young cowbirds from imprinting on their host parents.

Interesting info for sure! But how exactly do Cowbirds learn how to be Cowbirds and not pick up on the habits of their host families?

I’ll post more on that question tomorrow…
Photo by @sally_siko of Birdwatching NC
Canon 5DS