Last week I wrote about two green woodhoopoes that had a curious behavior of feeding other birds (see post Green Woodhoopoe: Nature’s Room Service) Well, I have another story for you; this one involves another male green woodhoopoe feeding another bird that did not want to be fed!
A few weeks ago, my coworker Mark was tossing bugs to a few of the insect eaters in Scripps Aviary at the San Diego Zoo. He had the usual line of characters waiting for a cricket to be tossed their way: the long-tailed hornbill was patiently perched, the white-crowned shrikes made their boisterous appearance, and the racket-tailed roller was sulking on her branch. All was going well when suddenly the woodhoopoe male landed in the crowd of gathered birds. He already had a cricket in his mouth, so Mark could only guess that he might have been looking for his mate to feed. Instead of finding his mate, though, the woodhoopoe inadvertently landed next to the racket-tailed roller. Surprised, the roller turned, opened her mouth, and prepared to roundly scold the woodhoopoe. Only she never got that far—she was interrupted. Before she could berate him, the woodhoopoe had deftly shoved the cricket into her gaping mouth, flown away, and (probably) congratulated himself on a job well done!
Okay, enough of the anecdotes, what’s really going on here? Are green woodhoopoes just oddly obsessed with feeding other animals? The evidence to me suggests “yes!” But there may be a reason nature has given woodhoopoes this quirky characteristic. Woodhoopoes are cooperative breeders; this means that a group of 4 to 8 woodhoopoes (sometimes up to 14 individuals) helps to raise the offspring of just the dominant male and female of the group. Who are these helpers? Frequently, the helpers are the offspring of the breeding male and female. In the wild, the tree-cavity nests woodhoopoes need can be hard to come by. With a lack of nests available, many woodhoopoes help to raise their siblings instead of starting their own family. The helpers may not have the genetic success of breeding, but they do help to increase the success of their genes if they improve the survival rate of their brothers and sisters. As time passes, the helpers may inherit a breeding position from their parents or they may strike out on their own and try to find a mate and a nest.
You can probably guess by now why woodhoopoes have a tendency to feed other birds: these helpers bring a constant supply of food to their siblings! Feeding birds that are neither their offspring nor their mate is not just a quirky characteristic of the green woodhoopoe but also a means of their survival. How cool!
Mike Grue is a senior keeper at the San Diego Zoo.