Warblers begin to arrive in the Northland

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When we reach the end of April we look around to see that the greening, mostly associated with May, has already begun. April with its changing conditions provided enough moisture, mostly as rain, to bring on the next phase of spring. Grasses, garden and lawn plants are the first to grow the new shoots of green but when we take a closer look, we see more.

I find it is the small plants, the mosses, that begin the greening in the woods. In many deciduous forests, a growth of ramps (wild leeks) takes over the forest floor as well. These days are an important time in the lives of the spring herbaceous plants so common now in the woods. Trees are later to open leaves and so the spring sunlight penetrates through the branches. The plants growing under this canopy take advantage of this lighted scene to turn green and grow quickly and flower.

Here are the first of the spring wildflowers. They will be abundant during the first half of May, but now some of the earliest ones can be found in bloom already. During a typical walk at this time I can find hepatica (always the first to flower), bloodroot, spring beauty, wild ginger, wood anemone, violets and trout-lilies. In the wetlands, marsh marigolds open their yellow petals.

This list changes and expands daily with each walk. Some of the woody plants here are starting to open leaves. Shrubs of gooseberry and honeysuckle are quick to start, but so is the small tree of elderberry. Soon lilacs, quaking aspens and cherries will be holding green leaves as well.

Frogs have been actively calling and breeding in the vernal ponds. The trio of wood frogs, chorus frogs and spring peepers, welcome the addition of leopard frogs as the spring advance. Also in the wetlands, the waterfowl of many kinds have come by, some to rest, others to remain and nest. Several species of ducks, geese, grebes, mergansers, coots, cormorants, swans and pelicans have all been noted in recent weeks. At the shoreline, great blue herons, sandhill cranes, along with sandpipers and other shorebirds, feed in the shallows.

And the time is soon to be upon us when we’ll also be looking at the arrivals of many of migrant songbirds. Juncos and other sparrows along with robins, thrushes, sapsuckers, flickers, kinglets and blackbirds have been with us for a couple of weeks already. These songbirds mark the beginning. Soon we’ll see the orioles, grosbeaks, hummingbirds, vireos and more. But none are so diverse as the amazing warblers.

Each spring the Northland is host to 26 kinds of these small birds. About half stay to raise a family here. The others move further north into the boreal forests for their breeding sites. Most are small, about 5 inches long. They tend to flit among the branches quickly and though many are yellowish, others vary in color and may be hard to identify. Indeed, seeing and learning all of these various species of warblers is a bit of a challenge.

The vast majority of these birds spends the winter in Central America or further south. They do not arrive back here until the greening leaves open in May. Their timing is such that they can feed on the numerous caterpillars that are quick to devour the recently formed foliage. (If spring is very early, this scheme can be impacted and throw the timing off.) They find ample insect food in the May trees. Their presence in the spring woods makes our walks here one of looking down at the spring wildflowers and up at the warbler movement in the trees.

There are a few kinds of warblers that winter in the southern parts of the United States. They do not have as far to travel when northing in spring, making their arrival early. Most notable of these is the yellow-rumped warblers. These spotted and streaked birds with yellow patches, including on the rump, have always been the first warbler that I see in spring.

This year I recorded one on April 9, about a month before most of the rest. They do feed on insects, but also eat seeds. (One came to my birdfeeder last year in mid-November.) Three other warblers, the orange-crowned, pine and palm warblers, also winter in the southern states and are usually the next ones to be seen here.

As the weeks of April pass and we emerge into May, the insects also become more common. This includes butterflies, bees, dragonflies and recently emerged black flies and mosquitoes, a good time for insect-eating birds to arrive.

Soon warbler species that make longer flights from Central America and beyond will be present in numbers and their variety will grow. We may quickly go from seeing one kind to four kinds to 10 kinds or more in our yards and woods as we go through this greening month of May. But it begins with just a few kinds in late April.