St. Paul, Minn. — It's officially meteorological spring, and we're not far away from the vernal equinox later in the month. So, while we still have monumental piles of snow, it can't hurt to check in on the perennial signs of spring.
Bird expert Carrol Henderson joined All Things Considered host Tom Crann from the Minnesota Department of Natural Resources to give a status check on the activity of our feathered friends.
Tom Crann: How are Minnesota's loons faring in the Gulf of Mexico? Will the effects of the oil spill affect their ability to return?
Carrol Henderson: We've had just an enormous amount of interest in finding out what is happening with the loons. We did mark some loons from St. John's University that have gone south, and we have one loon on the air at the Minnesota DNR website and watch the track of the loon. Most of our loons go into the Gulf of Mexico, and they actually change from a fresh water bird in the wintertime to a salt water bird in the summertime.
We know that some of the food creatures they depend on could have been potentially affected by the oil spill. The other problem we had is that the loon chicks hatched in 2008 and 2009 were in the Gulf at the time of the oil spill because they don't come back to Minnesota until they're three years old, and they don't reach sexual maturity until they're five.
We don't know much of our loon population could have potentially been lost. So, there's a big question mark as to what happened to the younger loons as well as the older one that went down there this fall.
Crann: You're putting little sensors implanted in the birds on the ones that you aren't tracking via GPS, right?
Henderson: Yes, the loons don't hold a harness very well because this would impair their ability to dive.
Crann: But, the ones into which you've implanted the GPS, what can you tell us about the data you have gotten back; anything unusual?
Henderson: Nothing too unusual. The loon, the individual one that we marked as a trial, went down just off shore from the Florida panhandle and then it has gradually worked its way down along the western coast down to approximately Fort Myers area. They winter off shore. So, this is not a bird that people will typically see on a Florida vacation because they're quite a ways out of the Florida coast.
They may dive and feed on the creatures that are right on the bottom, so this could expose them to materials that have settled on the bottom or at least picked up contaminants on the bottom.
Crann: So, it's going to have to be another cycle before we have a good idea of how this affected our population in Minnesota?
Henderson: Yes, in fact, next July we will have over 600 volunteers checking 600 lakes across Northern Minnesota checking loon counts.
We do this every year since 1994, and populations have been very stable. Now, we're looking for any possible change in numbers. We do have a new proposal that's being considered this coming Monday for money to do a loon and pelican study to see if there have been impacts from those populations because of the oil spill.
At Marsh Lake, in western Minnesota, we have the largest nesting concentration in pelicans in North America. We've got the mother load of pelicans. We've also got more nesting pairs of loons in the lower 48 states than in any other state. These are two species that we really are concerned about preserving and managing, and this new study would certainly give us the opportunity to see what has happened.
Crann: We didn't talk about the pelicans when we talked about the Gulf oil spill. Were they affected in any way? Do they go to the same place?
Henderson: Yes, most of the pelicans from Minnesota go down, and they ring the entire Gulf coast into eastern Mexico. The very young also spend their first year in the Gulf. So the young pelicans would have also been exposed to the spill. Those are the two species most vulnerable to the potential damages during the oil spill.
Crann: This summer you will have to do a count or census of the populations in the state.
Henderson: This new project we're proposing would include a statewide count on pelicans, which we did last year, so we have a nice control on what we did last year.
Crann: I want to ask you about robins. There have been some sightings here in the Twin Cities where we sit. Does that mean spring is on track, even though it doesn't feel like it at all?
Henderson: Actually, no. With robins, eastern bluebirds and morning doves, we've had a significant number of them stay north. Some of these birds don't even migrate south anymore because of a number of reasons.
We have other birds that come early, for example, the American kestrel. Bird behavior does change over time and it's fascinating to see these birds that we've long considered migrants now becoming permanent residents.
Crann: What are the signs of spring? What are the birds that are coming back that we're beginning to see?
Henderson: The great blue heron normally shows up on St. Patrick's Day, give or that a day. We'll also see flocks of Canadian geese showing up. A lot of birds on the shores of the St. Croix and Mississippi rivers are dispersing as the waters start to open up.
Crann: There appear to be more trumpeter swans visible here during the winter in this region.
Henderson: That's one of the reasons. One of the other things happening is that we did a count, cooperating with Three Rivers Park District and biologists this winter, and the statewide count came up with 5500 trumpeters in Minnesota, which is a doubling of their population in the last five years. They're showing up in many counties across the state that are places where they haven't been in one hundred years.
Crann: Why is that?
Henderson: They're rediscovering areas that they might have nested in pioneer pre-settlement times. As they produced their young they're exploring out in new places, so it's a really wonderful conservation success story.