With temperatures in the 90s in southern Maine this past week and schools finishing classes, it’s easy to feel as though summer is finally here. We tend to think of summer as the main nesting period for birds in our area and generally it is. But there is much variation, which begs the question, is summer really for nesting? Great horned owls may disagree, as they can start nesting in February. Bald eagles start in March, American robins in April, and (especially with climate change causing warmer weather to generally arrive earlier), a whole slew of warblers, sparrows, and other birds start nesting in May.

As we find ourselves sliding into mid-June, we have already seen young-of- the-year European starlings, black-capped chickadees, American robins, and killdeer, while a close watch of birds just about anywhere will reveal dozens of adults carrying food to recently hatched nestlings hidden away in a cozy nest.

Yet even as we may think of this time of year as the nesting season when birds are tied to a particular territory, it turns out that there are still a surprising number of birds that are either still migrating or are wandering around with no intention of trying to nest this year.

Amazing as it seems, there are a set of birds for which our marine waters in summer are their wintering grounds. These are a few seabird species—most notably, great shearwaters and Wilson’s storm-petrels-- that breed on islands in the sub-Antarctic during our winter and fly north to the other end of the world to enjoy our more amenable summer conditions when the brutal Antarctic cold descends on that part of the globe.

A number of birds, especially larger ones like some of the seabirds, take years to reach maturity and breeding condition. Species like the massive northern gannet can take four to five years before they are ready to find a mate and nest up on the islands in the Gulf of St. Lawrence and Newfoundland. Subadult gannets can often be seen offshore here in Maine during our summer as they hang out south of the breeding grounds and continue to mature. Gulls are another bird family in which the young take multiple years to reach breeding condition. During summer it is not uncommon to see immature Bonaparte’s gulls and ring-billed gulls loafing on beaches and around lakes.

Some long distance migrant birds are particularly reliant on finding high-quality food sources at migration stop-over locations in order to bulk up and make it to their far-away breeding grounds. Many Arctic breeding shorebirds like semipalmated sandpipers, black-bellied plovers, and sanderlings migrate through Maine on their way north. But some individuals just are not able to find enough food along the way and so stay somewhere along the migration route when the rest of their kin are up in the Arctic. It is not uncommon to see a few of these birds here and there along the Maine coast throughout June.

The day before we wrote this column, the Maine birding community was abuzz with news of the discovery of an immature magnificent frigatebird over Stratton Island and sometimes visible from the beach at Pine Point in Scarborough. This is an incredibly rare find here in Maine since frigatebirds are essentially a tropical seabird. In the U.S. one normally has to travel to coastal south Florida to have a chance to see one, and even there they are at the northern limit of their range. Frigatebirds are a species that has one of the longest subadult periods, sometimes taking seven or eight years, or even longer, to reach full adult plumage and breeding condition. Our Maine frigatebird visitor appears to be only a year or two old and is apparently wandering around to see more of the world before he or she decides to settle down.

Summer may be the nesting season for birds but not all birds are here to nest!

Jeffrey V. Wells, Ph.D., is a Fellow of the Cornell Lab of Ornithology. Dr. Wells is one of the nation's leading bird experts and conservation biologists and author of the “Birder’s Conservation Handbook.” His grandfather, the late John Chase, was a columnist for the Boothbay Register for many years. Allison Childs Wells, formerly of the Cornell Lab of Ornithology, is a senior director at the Natural Resources Council of Maine, a nonprofit membership organization working statewide to protect the nature of Maine. Both are widely published natural history writers and are the authors of the book, “Maine’s Favorite Birds.”