Food that helps the bluebirds during the storm
We have another storm moving up the east coast this weekend and I believe this storm will continue to put pressure on our insect eating migrants. I wanted to check all of the bluebird boxes but decided not to disturb the boxes until after the storm has moves through. I believe it is possible that the substances inside the box could help the surviving swallows stay insulated and I do not want to stress any swallows more than they could possibly be already. I did settle on checking the two boxes back behind the house where the Eastern Bluebirds were showing some interest in nesting. It was only a week ago when these two boxes were completely empty. With a closer inspection it appears the bluebirds have left numerous clues of how they are able to survive the snow storm that we had last week.
What I found interesting was the fact that the seeds were perfectly shaped without having been chewed up (as how the Purple Finch chew their seeds, see previous post). My guess is that the Eastern Bluebirds were swallowing the seeds/shell whole and since they have a fast digestive system that the seeds are quickly passing through their body. You can see a few shell casings of the Sumac (not sure why they didn’t get digested??) and without knowing for sure, I would guess many of these seeds are that of the Sumac. This is a perfect natural advantage in the Sumac to be spread around by the birds and probably one of the main reasons the birds leave these seeds as a last resort food. Without knowing much about the Sumac fruit, the seeds “could” have coating on it that “could” keep the seeds from being digested when eaten whole. I also will “guess” that when this coating is removed by the stomach of the bird that it helps the seeds germinate into a tree when fallen to the ground (via its droppings). But if the bird (or animal) chews the seeds that the coating will then be broken and the meat of the seed can be digested. Another option is that the seeds “could” give the birds the runs and then everything it eats will then runs through its body?? Your guess is as good as mine on why all these seeds were here and not digested. If anyone knows for “sure” please leave a comment!!
Besides the sumac seeds that I found; there were two insect casings and another unidentified seed in the scat of this bird (supporting that the seeds give the birds the runs). Obviously, it is only my SWAG (Scientific Wild Ass Guess) that this scat is really from the Eastern Bluebird and these seeds are that from the Sumac. Finding things can always get you asking more questions than answers!! But, checking the box was a wonderful way to learned more about the Eastern Bluebird’s spring feeding behaviors and it should be interesting in what I might find in all the other boxes I monitor.