For the Birds Radio Program: Evening Grosbeaks
Today’s For the Birds is about one of the greediest birds at Northland feeders. (4:30) Date verified.
In winter, when the world is a study in black and white, birds of the far north descend upon the Northland, bringing brilliant color to the barren landscape. The Evening Grosbeak, one of the brightest, most welcome of all, has a chunky body and thick beak, looking like a goldfinch on steroids. Right now its oversized beak is chalky white, but will turn lime green by mid-February as if in anticipation of spring. This color change takes place as grosbeaks come into breeding readiness, and the green color seems to elicit mutual feeding in a mated pair. Evening Grosbeaks aren’t particularly territorial, and many pairs breed in close proximity. After the babies fledge, they beg for and receive food from any birds with green beaks. I’ve watched a single baby grosbeak successfully beg from four different adult males in succession. It takes a village, or at least a flock, to raise young grosbeaks.
The grosbeak song has little of the melodic or tonal quality we associate with birdsong. They simply produce conversational chatter. In winter, grosbeaks come in two plumage types, male and female, but come summer you can pick out immature males and females as well as adults. The one fatuer that all males share is large white wing patches. A few weeks ago, I talked to a listener from Canyon, Adele Crusz, whois getting a beautifully odd male grosbeak at her feeder. He has no dusky or black feathers, and so may not have been able to produce melanin pigments, but still produces carotenoids, making him pure lemon yellow with white wing patches. She sent me a photo and he’s gorgeous.
There are many records of pure white albino and partial albino Evening Grosbeaks, and even a handful of cases of “gynandromorphs”—bizarre birds that are literally half male and half female. Inside a gynandromorph, one side has a functional testis and the other a functional ovary. Outside, the bird likes as if half of a male was stuck to half of a female. Although you are not likely to see a gynandromorph at your feeder, there’s one in the collection at the Bell Museum of Natural History.
Evening Grosbeaks take their name from the mistaken belief that they sing more in the evening than at any other time, perhaps because the early ornithologists who named them didn’t have many opportunities to study them. Before the mid-1800s, Evening Grosbeaks were unknown east of the Great Lakes, expanding their range as settlers brought western maples and box elders to the East.
I’ve been blessed with many more Evening Grosbeaks at my feeders than most of my friends. I’d like to take credit for this, pretending that my yard has a uniquely benevolent aura or that my feeders are superior, but the simple truth is that my yard has a box elder tree in it, and Evening Grosbeaks love to eat box elder seeds. These seeds cling to branches for months, and their fluttering and waving lure overhead flocks out of the sky. Once they’ve come down to a tree, it’s easy to spot nearby feeders. So the single best method for attracting grosbeaks is to plant box elders and wait. And wait. It’s much quicker to set out sunflower seed feeders. In a good year, once the grosbeaks finally notice a feeding station, they’ll be regular visitors.
Grosbeaks seldom visit feeders with view-obstructing roofs or sides, preferring open platforms. They crowd together, each one defending a small personal space by bonking any others who come too close. You don’t have to watch them very long to figure out how much space each one needs. But whether they’re bickering or getting along, their soft chatter and beautiful plumage make them as welcome as sleigh bells, and a lot warmer.