Wild Side: Fish may snack on birds occasionally, but not often
Do fish eat birds? I have had to answer this question before, especially when duck broods first hatch, and their numbers mysteriously dwindle. I have heard tales of largemouth bass, muskellunge, and northern pike pulling ducklings under the surface never to reappear. There have been many studies on the stomach contents of large predatory fish like muskies. I have examined research, and from what I see, birds are rarely their prey.
That’s not to say that fish never eat birds, just that birds are a pretty small part of their diet. I am guessing that a bird moving a certain way would trigger a fish to strike, an instinctive reaction that results in the bird being consumed. I know that fish eat other kinds of wildlife, like snakes, frogs, salamanders, and mice; birds would be far less common.
On the other hand, birds definitely eat fish. Eagles, osprey, kingfishers, pelicans, cormorants, herons, and mergansers are some piscivores (fish eaters)-and don’t forget loons. I was discussing this topic with my counterpart, Fisheries Biologist John Kubisiak. I asked him if he wouldn’t mind providing a counterpoint in the discussion from a fisheries standpoint. What follows is John’s thoughtful contribution:
As a Fisheries Biologist, I occasionally hear from boaters or lakeshore residents who are concerned about the loons on their favorite lake. My first response is usually “They eat fish, don’t they?” If you read between the lines, you might think I’m asking “My job is to manage fish populations and loons eat fish, so why should I be concerned about a loon’s welfare?”
A couple springs ago, Fisheries Technician Steve Timler and I set nets on one of the Oneida County lakes we manage. About 2 days later, as we pulled into a bay to lift a fyke net, a pair of loons swam over to check us out. The loons had just returned from their winter quarters in the south, and were back in their nesting territory. Given all the boat traffic and human activity Northwoods loons are exposed to daily, our netting boat easing up to a net must seem fairly unobtrusive. This scene was repeated daily when we lifted the net – the loons would swim close, sometimes right up to the boat.
It may be hard to believe, but loons really seem to like Fisheries staff. They often come over when we run our nets, and we’ve had a number of instances when loons built a nest very close to a net after we set it. Perhaps these birds instinctively know that anyone who handles fish for a living must be basically good. Or maybe they just want to get at the fish we handle. If loons could salivate, I imagine their black bills would drip with drool at all the fish we pull out of a net. Whatever the reason, I’ll take all the support I can get, even from a “loony” bird.
I was a little surprised a couple days after the loons started visiting, to find that Wildlife Management staff had received a complaint about my netting activity. The caller was concerned that I was disturbing the nesting loons, and furthermore the bay was now posted off-limits to boaters. My immediate response was “Loons … they eat fish, don’t they?” My second defense was “My net was set before either loons or signs appeared, so I was there first. Besides, those signs are voluntary.” I then explained that “Loons actually like Fisheries staff, so I’m sure they won’t be disturbed as long as the boating involves fish.” Luckily for me, the Wildlife Management staff is more tactful than I, and smoothed things over until I could finish the netting survey.
Ultimately, as different as fish and birds are, the life cycles and habitats of some have a surprising amount of overlap. In the end, though, it seems the birds usually come out ahead.
Jeremy Holtz is a wildlife biologist with the Wisconsin DNR and writes a weekly column in the Star Journal. To contact him, call 715-365-8999.