As we head into spring, many species of birds are migrating north to Maine, sometimes in large flocks or as individuals. The goal is to get to their nesting grounds, where they will find a mate, pair up, and hopefully raise a family. It was thought-provoking when Rosie Bensen of Newcastle wrote in asking about seeing birds in groups of threes.

Black-capped chickadees visited their feeders in threes, crows were reported in a group of three, and most recently, a “threesome of tufted titmice (were seen) sproinging about.” Three may just be Rosie’s lucky number, but I decided to dig through the literature to find a more science-based answer to the frequent trios.

The quick answer is that depending on the species, and the time of year, it is quite common for them to end up in small flocks, and often that is a group of three. This more likely occurs amongst species that are more social (think chickadees and titmice that you’ll see leading foraging groups), and more likely outside of the breeding season, because, well, three is a crowd.

Addressing the species Rosie mentions, we can start with our state bird, the black-capped chickadee. It is common for chickadees to form flocks in the winter, and these are usually made up of the birds that breed locally, plus the unrelated young that hatched outside of that area. The local birds want their young to disperse but will accept young from outside, called “winter floaters,” because they will have a lower rank in their social structure. These winter floaters are tolerated, probably thanks to safety in numbers and other benefits to the group, but they are quick to fill the void when a higher-ranking member disappears.

It is common, at the start of the breeding season, to see a trio of chickadees, made up of a high-ranking male, his partner, and one of the low-ranking males. That low-ranking male is unlikely to breed that year, but is ready if the opportunity arises.

Tufted titmice are very similar to chickadees in their social structures, so it won’t be much of a surprise to learn that they form small groups, too. I did find more specific research, led by Elena Pravosudova for Ohio State University, which in 1999 showed that the winter flock compositions will change based on forest sizes. To oversimplify, in most forest fragments they found that flocks consisted of a pair of adult titmice and one immature bird (born over the past year). If they were from a large forest (10-20 acres), then it was more likely the young were the offspring of that pair. However, in smaller forests, the young were more likely to disperse from their natal grounds, leaving their parents and joining other titmice even in equally small forests. Despite the increased competition in these small forests, all of the birds benefited from better predator detection and had more success finding more food.

Crows are another species with amazingly high degrees of sociality, especially cooperative breeding. Unlike the two birds mentioned above, American crows will have “helpers” at their nest, which can be year-old birds sticking around, or sometimes other adults. These additional birds will help with everything from defending the pair’s territory to feeding the females while they are incubating.

This is a great time of year to be getting outside as frequently as possible to see birds migrating back and watching for their early breeding behaviors. See if you can spot groups of crows with helpers in tow, or look for species on the other end of the spectrum, like male ducks who will ditch their families just after finding a mate.

OSPREY GOOSED OUT OF ITS NEST

We’ve received some interesting questions about the drama unfolding in South Portland between a Canada goose and an osprey. I first learned about this thanks to photos by Tony Gedaro on the MAINE Birds Facebook group, showing a pair of Canada geese occupying an osprey nest at the end of a long pier. Recently, the osprey has returned, which brings up the question: Who will prevail?

First, we should consider that by mid-April in southern Maine, many Canada geese have already laid eggs and have begun incubating. Osprey, on the other hand (or talon?), are just returning after spending the winter farther south. If you’ve ever walked by a nesting goose, they are not shy about expressing their displeasure with your presence and will hiss and sometimes charge to keep you away. When a nearly 10-pound goose with a 5.5-foot wingspan is coming at you, you move. Even an osprey, with about the same wingspan but only one-third the mass, probably won’t think twice about moving away from that unstoppable force.

Most geese will nest on the edges of ponds, or on little islands or elevated patches near water, but sites like the osprey nest in South Portland aren’t unheard of. There are many documented nests in trees or on cliffs. Many questions center around how the goslings will be able to make it down from the nest 40 feet above the end of the pier. I found an entertaining answer in an account published in The Auk in 1973. This report was from Alberta, of a (Canadian) Canada goose that nested in an old ferruginous hawk nest, located 50 feet up a cliff. The observers watched the goslings fledge and noted that instead of previous accounts of goslings “jumping from nests,” they suggested “a more apt description of the departure … would be to say the goslings walked off the nests.” All those goslings survived their tumbles, one a bit shaken, but none sustained any injuries.

Time will tell what happens with this nest, but from my own experience with aggressive geese, I’d bet we see goslings hopping and walking down that pier in a month or so. And I’m not usually one to recommend anyone spends time on Facebook, but if you’re going to, the MAINE Birds group is always entertaining.

Do you have a nature question for Doug? Email questions to ask@maineaudubon.org and visit maineaudubon.org to learn more about birding, native plants, and programs and events focusing on Maine wildlife and habitat. Doug and other naturalists lead free bird walks on Thursday mornings, 7 to 9 a.m., at the Gilsland Farm Audubon Sanctuary in Falmouth.