Every now and then I come across something in nature that really grabs my attention. Recently I have been concentrating on photographing birds feeding their young while they chicks are still in the nest. I have spent countless hours waiting (covered in camouflage and hiding as to not disturb the family and also to catch natural behavior) at several nests. Of course in the recent heat I can say this is not my favorite thing to do but it did prove very interesting last week.
As you may recall from my last column, I was photographing an American Goldfinch nest and in the process learned a lot about the extremely nutritious food that they feed their babies. The mixture of partially digested and regurgitated seed pabulum the parents feed their young means the babies need to be feed only once every 2 hours as compared to similar songbird species who feed their chicks insects once every 20 minutes or less.
Last week, while working with one of my favorite species of bird, the Eastern Bluebirds, I photographed something very unusual. For days I watched as both bluebird parents came to the nest cavity with all sorts of insects–crickets, katydids, caterpillars of many species of moth and butterfly, spiders and much more. Each trip the parents stuffed the insects, large and small, into the gapping mouths of their hungry nestlings. Nothing too unusual here.
Then one afternoon I saw the adult male bring in something fairly large. I wasn’t able to see at first what it was. As the male Bluebird entered the nest cavity I took a series of pictures and he departed to gather up more food. I didn’t think much of it. Just another mouthful of protein rich, six-legged goodness I thought.
Shortly afterwards the male Bluebird came in again carrying another large food item. Again he entered the nest box to feed his youngsters and again I took a series of 8 to 10 images. Off he went again in search of more food. By the way, male bluebirds do most of the feeding of their young. Females also feed their babies but only at a rate of about half that of the male.
I quickly removed the flash card from my camera and placed it into my computer to take a quick look at the images and make sure my focus was accurate and exposure was correct. To my astonishment there on my laptop screen was the male bluebird feeding an adult Western Chorus Frog to his babies. Not just once but twice in less than two hours.
As I sat there with my jaw hanging open, many things raced through my head. This means that the bluebird had to first find the frogs. If you have ever tried to find a Western Chorus Frogs you will know what I mean. They are small frogs that don’t move around a lot during the day and they blend into the surroundings so well, that I have been within 2 feet of them and still couldn’t see them.
So after locating the frog the bluebird needed to catch it, another difficult prospect, and then dispatch it. Larger birds wouldn’t have much trouble killing a frog of this size but frankly the Eastern Bluebird is not well equipped for such a task. I have watched bluebirds kill caterpillars and large insects thousands of times. They simply whack the prey item against a branch until dead. Somehow, I had troubles imagining these sweet bluebirds beating the stuffing out of this frog, but apparently it did because here it was and the frog was not kicking.
My mind then jumped to wondering about how the baby bird’s digestive system was going to handle the bones of the frog. Most birds of prey for instance are unable to digest bones of the animals they eat. They regurgitate the undigested bones up several hours after eating. As far as I know regurgitating is not something that bluebirds are capable of doing.
Later after returning to the office I did some research. The only documentation I could come up with was some reports of bluebirds feeding their young frogs and salamanders back in the 1940’s. This would have been before the nation-wide population decline of the Eastern Bluebird. So if you have any unusual sightings of bluebirds eating strange things, why don’t you give me a shout.
Just about the time I think I know something about nature she seems to throw me a curve ball. In this case it was a curve ball in a frog’s skin. Until next time…