This past week many a backyard, park and preserve has been flooded with boreal migrant songbirds, particularly yellow-rumped warblers and white-throated sparrows. While both species nest in Maine, during migration our local breeders are augmented by huge numbers of migrants returning to the Boreal Forest Region of Canada, where the bulk of the world population goes to raise their young. In fact, populations of each of these two species are estimated to number over 100 million, and Maine is lucky enough to host a lot of them on their way north. Male yellow-rumped warblers are a gorgeous blue color on the back and head contrasting with a bright yellow rump, which is why birders often refer to them affectionately as “butter butts.”

Viewed from the front, they show two bright yellow spots on the sides of their breast, giving the impression of oncoming headlights of a car at night. Often at this time of year, “butter butts” can be seen foraging low in bushes, in newly flowered maples, or just-leafing crabapples as they search for insects. This gives us humans opportunity to approach close for stunning views.

White-throated sparrows are one of the other common boreal migrant species, but they are often heard more than seen, when they utter their loud, quavering, whistled “Old Sam Peabody-Peabody-Peabody” or as our Canadian friends prefer, “Oh-Sweet-Canada-Canada-Canada.” Either way, it’s a memorable and easy-to-learn song, and even in migration, the birds will break into the song as the make their way north through Maine to Canada’s Boreal Forest.

A new report entitled “Boreal Birds Need Half,” recently issued (with Jeff as lead author) by the Boreal Songbird Initiative highlights the importance of the Boreal Forest for the birds that people in the United States come to expect in abundance during migration and winter. Between one and three billion individual birds of 300-plus species are estimated to nest in North America’s Boreal Forest, the billion-plus-acre expanse that extends from interior Alaska across Canada all the way to Newfoundland. Nearly 100 species are reliant on the region to support 50 percent or more of their entire population.

The reason that the Boreal Forest Region hosts such an abundance of birds is because it is also one of the world’s last, very large areas of intact so-called “primary forest” that has never been impacted by modern human industrial endeavors. More than 70 percent is still ecologically intact, with much of it remote from all but the Aboriginal peoples who have lived there for thousands of years. The report describes the new conservation science that shows that in still-intact areas like the Boreal Forest Region, maintaining the full abundance and diversity of birds and other wildlife will require balanced planning to protect at least half from large-scale industrial disturbance while using world-leading sustainable development practices in the parts that are used for industrial development.

Fortunately, two of the largest provinces where many of our migrants may be headed, Quebec and Ontario, have commitments in place to protect at least half of their Boreal Forest Region. That should help ensure that our grandkids will be able to enjoy those yellow-rumped warblers and white-throated sparrows in their backyards, too! You can find a copy of the new report at borealbirds.org/birdsneedhalf.html.