ASK A SCIENTIST: Michale Glennon on boreal birds

A: The Adirondacks is an interesting place because we really do sit on the border between the real true boreal geographic zone and the temperate zone. The overwhelming majority of that [is] what we would call temperate forests, northern hardwood forests. But because we are on the border between those two zones, we get a lot of mixing.
Because the park itself sits on this sort of uplifted chunk of the Canadian Shield, we have temperate woods that have these little pockets of stuff that look like you got picked up and moved 500 miles to the north. 
And so we do have boreal habitats– bogs and things are not necessarily rare. We see them all over the Northeast. But I think what the Adirondacks has that distinguishes us is the scale of some of them: places like Spring Pond Bog, which is 800 to 1000 acres. We don’t see too much in other areas of the Northeast other than northern Maine, and to the south of us it’s all spots that are much smaller. 
They’re significant as opportunities for us to see what’s happening on the southern extent of the habitat itself, and to the species that inhabit those places. It’s a good climate change bellwether, because we know that [since the target species are] already on the range margin, they’re already going to be at a disadvantage compared to species that are in the heart of that habitat more to the north. Conditions on the range margin are already going to be more stressful. So we’re likely to see those changes more quickly here. At the same time, I feel that we are lucky to have these habitats. I think they are important in the psychology of the Adirondacks. They are…some of our most Adirondack kind of icons. It gives us a feeling of northern-ness. And so I feel fortunate to have the habitats and the species and the opportunity to see them.

A: I would suspect that it would. Gray jays [have] been studied in Algonquin Park and Canada for a long time. And one of the ways that they sort of get away with nesting in wintertime is to cache a bunch of food. So they have this crazy sticky saliva and they collect food sources, invertebrates and seeds and things and store it by tucking it under bark in trees. Some work in Algonquin Park has found that they have suffered from warming fall and winter temperatures because those food caches are spoiling. So that is an easy-to-see impact from changing winter conditions on a resident bird that’s here all the time. 
It’s harder for me to figure out all of the connections between the signals that we saw in winter precipitation and temperature, and how that would impact the birds that aren’t here in the winter. If it’s warmer, if more of the precipitation is falling as rain rather than snow, it changes the snowpack, it changes the insulation. How does that impact the plant communities which are important food sources when these birds come back, and similarly the insect communities that live on those plants? Birds have been adapted to the timing of that for millennia, arriving and having young at the perfect time when those food resources are at their highest levels and then if winter conditions mess that all up I can see how that could also impact the spring migrants when they come back. 

A: There might be short-term benefits of warmer temperatures – for example, more insects are associated with higher temperatures, so more food resources. But when we think about that same combination of warm and dry over the long term, [it] has the potential to change these habitats from what they are now to something that’s different. And that’s because the open peatlands are sphagnum-dominated habitats. Long term I think it will change these habitats into a more forested system. Some of these species are okay with that and some of them will be less so and in some cases, the more generalist forest birds may outcompete them when we get to a point where it’s more like that. 

A: This is still a process that takes some time. The birds I think are responding more quickly than the trees will just because their lifespan is different, and they are mobile, and they can move in the landscape much more quickly than the trees and the plant community. Part of what we learned from this research is that (various wetlands) all operate as sort of a network on the landscape. There’s the big, enormous spots that are probably source habitats where more young are produced than are lost. They export individuals to other sites, and then there’s the smaller [habitat], isolated, farther away, more encroached by development and roads. And so I think that there’s a huge role for the state, for towns, for individuals, to think about the smaller ones, because they’re still going to be important for (birds) that are able to move into the better habitats eventually as stopover habitats during migration. Acquisition is nice, but I also think that there are ways to try to steer development away from these smaller spots, try to be cognizant of where we put trails and, you know, give them sort of a buffer, [and] work with forest management entities. It would be nice to see some more attention paid to the smaller (parcels). 

A: Yeah, I think so. There are four or five species that are documented as being in the Adirondacks and they were on our original list of target species. And I hardly ever find them. Maybe they were once some of the ones we’re studying and they’ve already retreated, and they’re breeding to the northwest. They might represent the future for some of the ones we have tracked.