Although our day-to-day routine in the field varies slightly, the one aspect of the work up here that we always focus on is nest searching. We might be doing surveys of the snow cover one day or banding birds the next, but whenever we are away from the camp we are invariably doing our utmost to discover as many nests as possible. As I touched on briefly in a previous post, we generally locate the nests by cluing in on the behavior of birds or flushing them off their nests.
We keep track of the nests of every species here except one, checking them at least every five days from the day they’re found until the eggs hatch. The exception is Lapland Longspurs, which are not of interest to this study, and are so abundant that it is not unusual to find 5-8 of their nests in a day of just walking around. It is fascinating to see the differences in nest finding between each species, how they vary in behavior and response to our approach. I won’t describe every one of the species that do nest here since there are so many, but the five species that we are focusing on in this study showcase the spectrum of behavior quite well. Our five focal species are all shorebirds, and more precisely are Semipalmated Sandpiper, Pectoral Sandpiper, Red-necked Phalarope, Red Phalarope, and Dunlin, listed in order of abundance of nests.
The Semipalmated Sandpiper, shown above, is our most abundant species here by far, often making up half of the total nests found in a season of all species. They are one of the easiest nests to find in my opinion, so that is likely a large part of why we find so many. They tend to flush up off the nest at between 5-30 yards, which is close enough so that you can often tell the exact spot they flew up from and walk right to the nest, but also a sufficiently large distance that you have a good chance of popping them up when walking through an area. Once flushed, they usually stick close and give a distinctive call that usually indicates they have a nest nearby, just in case you weren’t convinced yet, and will usually sneak back to the nest almost immediately. These serve as the basis of behaviors that we look for in birds with nests, and are a good baseline to compare other species to. Sometimes you won’t see a bird jump off a nest, but then you’ll hear the distinctive call, get a sense of the location, and find a nest after watching the bird for just a couple minutes. These guys tend to like drier ground, and will often line their nests with nice white lichens.
Pectoral Sandpipers are our second most regularly found nest, but they have a whole lot more deviousness to deal with. Due to the breeding strategies of this species, however, you can discount half of the individuals immediately if you can tell whether the bird is male or female. Pectoral Sandpiper males will never be at a nest, and have no role in the parental care, so if the bird isn’t a female, it isn’t going to lead you to a nest. The distance that these will flush is usually 15+ yards, and can often be upwards of 50 or 100 yards. This means that if you’re not looking at the horizon as you’re walking, they will often pop off and fly far away, so when you reach the nest area you have no idea that there was ever a bird there. We will often find Pectoral nests later in the season that have been there for weeks, and have just been eluding us all along. Well over a half hour can pass before some females will go back to their nests, so patience and a bit of luck is required to be in the right spot at the right time when she returns. The combination of long flush distance and time away from the nest makes these on the tougher side to find sometimes, and some of the nest searchers here are frequently frustrated by a tricky Pectoral. They tend to nest in drier habitats, but will sometimes be on small dry patches surrounded by swampiness.
Red-necked and Red Phalaropes are similar to Pectoral Sandpipers in that you only have to worry about half of them – but in phalaropes, those are the males! The gender roles are reversed in phalaropes, where the females are the snazzy-looking ones that compete for male attention, and the males build the nest and incubate the eggs. At the start of the season, we will see lots of pairs hanging out together and after a certain point the females lay their eggs and depart, leaving only lone males. Phalaropes are unique among the shorebirds in that they spend their migration and winters mostly offshore in the oceans, returning to land only to breed.
They are much more adapted for water as opposed to shore, and are almost exclusively found in or next to water. As is to be expected, their nests are usually near water, scarcely further than 6 inches away from some pool or ditch. It is amazing some of the sites they choose – small tussocks of vegetation isolated in a large marshy pool, with the grasses tucked neatly around the nest in such a way as to render it almost invisible from above. Phalaropes will sometimes sit on the nest until you’re feet away, looking up and pretending they’re not there until you almost step on them. They also add another dimension to the finding process in that they will often walk off of the nest and fly up five or ten feet away from the actual nest, deluding you into thinking you know where they came from, until you realize you’ve been duped yet again.
Last but not least, the Dunlin. In my opinion, Dunlin are by far the craftiest and sneakiest of nesters up here, often leading you on a merry chase for the better part of an hour, only to leave you no closer to finding their eggs than when you started. Most Dunlin encounters begin when you hear the bird, and then look up and see it standing there watching you calmly, showing its unquestioned superiority. They will often flush at between 100-200 yards, so when you arrive in the area they will be very far from the nest, or not even around. Usually you have to visit the territory of a Dunlin a good half-dozen times before you finally track down the nest, sometimes crawling over ridges and watching from a distance while someone else walks up and causes the bird to fly off the nest. It can get pretty personal, and we only have 10-15 nests of this species a year usually, so any day that you come back with a Dunlin nest is a good day. They are also very site faithful, and sometimes will even use the same exact nest cup from year to year, cutting down the area that you have to search if you can find a banded bird from a prior year.
So there is a rough sketch of some of the trials and tribulations of searching for nests, and the sorts of things that we have to keep in our minds on a daily basis. You could be walking along and flush a bird up at 20 yards, and the first reaction will be “Pectoral!”, only to realize after a few seconds that it is a male, and that it won’t lead you to a nest. Or sometimes you won’t see it well enough to see it is a male, and waste 10-15 minutes watching a bird before coming to the realization that it has all been for naught.
As the season winds on there are fewer and fewer new nests, so each one becomes more coveted and challenging to find, since the areas that are frequently walked have already been pretty thoroughly canvassed. Soon we will be having nests begin to hatch, which opens up a whole new dimension, since birds with chicks act like they have a nest nearby, even though they’re mobile with their young.