Probably the question I am most frequently asked by people who have been feeding birds in the area for many years is, “Where have all the grosbeaks gone?” I wish I could give them a good answer, and I also wish I could bring them back.
First, I try to ascertain that they are referring to the evening grosbeaks because we have other grosbeaks in the area. Usually they describe them as the fairly big birds that are yellow, white and black, and used to come to feeders in droves.
Evening grosbeaks seem to be erratic wanderers. They are birds of the boreal forest, which are found all across northern Canada and down the Appalachian and Rocky mountains where the altitude produces the same growing conditions but many times in winter, they move down into the border states by the thousands. This phenomenon is known as an irruption.
These unpredictable movements, or irruptions, of birds bring evening grosbeaks down out of Canada at infrequent intervals. When we first moved to Evergreen, we had a few evening grosbeaks at our feeders most of the time, a few pairs nesting in summer and a few more in winter.
Then in the late 1970s and the early 1980s, we experienced a mammoth irruption of these handsome birds. Everyone we knew was practically going bankrupt feeding these huge masses of evening grosbeaks.
We had three sunflower seed feeders that held about 10 pounds apiece at that time, and we were filling them every day and sometimes more often. Everyone was building bird feeders, and the ingenuity was amazing. One gentleman had soldered ends on to gutter pipe and had what I told him looked like miles of gutter pipe running around his yard. The grosbeaks lined up along the gutter pipe, and it was fairly easy to estimate the number present.
Another man had given up on small commercial feeders and had purchased a full-size 4x8 foot sheet of outside plywood, put a molding around it and put it across the corner of his deck railing. That made a 32-square-foot feeder and it was often completely covered with grosbeaks.
By spring the flocks began to dribble away and only a few remained in the area to nest. This pattern went on for several years. Then just as suddenly as they had come, they stopped coming in such large winter numbers.
What caused these years of big irruptions is not known for sure but one suggestion was a shortage of food in Canada. This would include seeds of pines, spruce and firs, as well as box elder trees. It would also include a decline in spruce budworm larva, which along with other insects are a substantial part of their diet. They also consume a great deal of wild fruit such as choke cherries, service berries, etc.
Other suggestions were: especially severe winters with unusual cold and snow in Canada, which could send them farther south: the climate change, which could cause deeper snow in the boreal forest, making it difficult to find food; or perhaps the shrinking of the size or amount of boreal forest due to shale oil development.
Whatever caused the winter influx of these birds, it is not surprising that there were high numbers of them around Evergreen for there have always been small numbers of them, which have nested in our boreal forests every year. They probably showed the others the way. What is most puzzling is that after being here in huge numbers for about 10 winters, they just mysteriously disappeared.
I have none at my feeders now, but that is not to say that there are none around. I have heard of three here or four there, even of six at a feeder at a bit higher elevation, but there are no big irruptions of thousands of birds.
One of the things I learned about evening grosbeaks during those years of plenty was that they did a courtship dance much like a miniature turkey. We had a ponderosa pine, which was too close to the house and was rubbing the roof and the patio wall. It had to be cut down, so we had the stump left about six feet high. We placed a platform feeder on top of it. This apparently made them feel quite at home, and we had 50 or so grosbeaks at a time on this feeder. One day while I was sitting on the patio watching them eat, a female followed by a courting male flew toward the feeder. She landed on the feeder and began to eat, but it was apparently too crowded for his liking.
He landed on the patio wall where she could see him and suddenly began dancing. He stomped his little feet like a prairie chicken with his tail raised and fanned out like a turkey. He extended his wings on either side, drooping them toward the ground and vibrated them until they quivered and tilted his head up and back toward his tail during all of this his little feet continued to dance in tight circled.
After a few minutes of his strutting display, she seemed to ignore him and flew away, and he followed. That year we had a few pairs nest in our valley: one pair in our yard, one pair in our nextdoor neighbors and another pair or more in Bell Park.
One thing about evening grosbeaks, they are noisy birds. They have a loud call note, which is supposed to keep the flock together when feeding but it is an unmistakable call and can be heard from some distance.
This handsome bird can be found in the Rocky Mountains as far south as well into Mexico. We may well have another irruption of them some winter for they are alive and well in many places. Be sure to listen for them when hiking or driving around. If they are around you may hear their noisy chatter long before you see them.
Both the male and the female make this loud talk and apparently they were never taught not to talk with their mouths full. A flock of males and females talk vociferously while eating, and their loud shrill “pete or p-teer” can be heard a block away. They also have some more soft and liquid notes, which is considered to be a song and is probably more romantic.
If anyone has evening grosbeaks at their feeders this winter, I would be happy to hear about them. Please call me and let me know how many and where, especially if you see them on Christmas count day.