July 1, 2012 - Warblers - Grand Marais Visit

Diana and I just returned from five days in Grand Marais, MN. I was up early each morning exploring the back roads of this far northeastern part of our state. As a result, I had great looks at some of the warblers that nest in the boreal forest. All of these warblers are small birds, measuring 4½ to 5½ inches long. This is a male Magnolia Warbler.

WarblerMagnoliaForestRoad158CookCounty20120628

Here’s a male Canada Warbler. Notice this bird’s black “necklace”. It’s always mentioned by the guide books as a good field mark for this species. However, in studying this photo I found two other characteristics I hadn’t noticed before. The first one is the intricate black and blue pattern on the top of its head. The other thing that caught my eye was the eye ring which is half yellow and half white. I don’t recall seeing a two-toned eye ring on a bird before. Field guides do mention the prominent eye ring of this bird. Some say it’s yellow and others say it’s white. Apparently it can be half and half as well.

WarblerCanadaForestRoad158CookCounty20120628

This is the height of nesting season and adult birds are busy feeding babies. This male Mourning Warbler has a green caterpillar for his young ones. Actually, these caterpillars must have been pretty common because I saw several birds carrying them in their bills.

WarblerMourningmalecaterpillarForestRoad140CookCounty20120626

The person who gave the Nashville Warbler its name first saw one near Nashville, Tennessee. However, the bird was just passing through during its migration to nesting territory in the northeastern United States and southeastern Canada. There’s also a population that nests in the west coast states. Nashville Warblers build their nests on the ground, hiding them in the tall grass or among the ferns. During the winter, most of them are found in Mexico. You can just barely see the chestnut colored feathers on the top of this bird’s head; they are usually difficult to see in the field.

WarblerNashvillecaterpillarForestRoad153CookCounty20120625

This energetic singer is a male Yellow Warbler. I found him right along the water in the Grand Marais harbor. Yellow Warblers nest from the Arctic Circle through all of the United States and Canada. Some even nest in Mexico. Their nests are pretty easy to find. Cowbirds take advantage of this and often lay their eggs in a Yellow Warbler nest. If the female warbler discovers a Cowbird egg, she might give up on her eggs, build another nest on top of the first one, and lay another set of eggs. There is a record of one nest with six layers of eggs.

WarblerYellowGrandMarais20120627

Yellow-rumped Warblers don’t migrate to the tropics in winter; they stay in the United States and move to the south. They just switch to eating berries instead of insects. Because they don’t have so far to travel, they are one of our earliest spring migrants. The two somewhat different looking subspecies were formerly considered separate species. Birds in the east were known as Myrtle Warblers and those in the west were called Audubon’s Warblers. They were found to be very similar and both are now considered to be Yellow-rumps.

WarblerYellowrumpedForestRoad158CookCounty20120628