In my office I have a photograph of two bald eagles in a nest with two young hatchlings. The eagles built it about 10 years ago in a tall sycamore tree adjacent to the Quinebaug River. The nest is at least six feet in diameter and was constructed with sticks laid out and heaped onto horizontal branches snug against the trunk of the tree.

Hanging from my bookcase I have a tiny nest built by a red-eyed vireo. I discovered it hanging on a twig of a shrub last winter. It is perfectly round, barely two inches wide at the opening and two inches deep. Into a fork of the twig it has been carefully woven together with thin strands of reddish bark stripped from wild grape vines, bits of grass and thin roots.

The juxtaposition between our region’s largest nest and one so small has me thinking about the springtime activities of nest-building, laying eggs and hatching new life.

I recently purchased a delightful book, “Secrets of the Nest: The Family Life of North American Birds,” by Joan Dunning. The book describes in exceptional detail the nests and breeding habits of several bird species and includes beautiful illustrations by the author. Dunning’s book provided the inspiration for this column, and information gleaned from it as well as my own observations will be found ahead.

Dunning uses simple classifications of nest types and describes each nest type in detail for 34 bird species. Her classifications include ground nest (eggs laid right on the bare ground or in a slight depression), platform nests (piles of sticks laid and heaped together in trees or on ledges), burrow nests (nesting holes dug into the earth), cavity nests (nests built in holes in trees), cup nests (woven nests of vegetative material attached to trees or bushes), pensile nest (a suspended nest hanging from above like a hammock woven into the fork of a twig), pendulous nest (a hanging pouch woven suspended from thin twigs at the ends of a branch), no nest (parasitic birds don’t build a nest, but instead lay their eggs in the nest of another species).

This is the time of year when I often see killdeer foraging along the sandy banks of rivers, lakes and ponds. They’ll scurry along the shore, and if I get too close they may fly off a short distance. But if the killdeer makes a distracting broken-wing display, then I know a nest is nearby.

The ground nest of the killdeer is almost impossible to see, though it may be right at your feet. The nest will hold four dark and speckled eggs perfectly camouflaged to blend in with the rocks and sand. Both adults will help incubate the eggs for about 25 days.

In The Last Green Valley, we know of at least seven active bald eagle nests. These platform nests are massive in size and weight, due in part to the fact that the eagles will continue to add new branches to the nest each year and will use the nest year after year.

Other platform nests in our region include osprey, frequently seen built high on top of electrical power lines that traverse throughout the area. Less visible and usually in more remote areas are the platform nests of the Great Blue Heron.

Heron “rookeries” are several nests together built in tall dead trees within a flooded area (beaver pond) or marsh. The flooded area creates a natural barrier and protection from tree-climbing predators. While typically solitary in their hunting habits, the heron prefers the company, and safety in numbers, of other herons in its nesting habits. The nest itself is a loose collection of sticks lined with finer materials. Between three to six blue-green colored eggs are laid with incubation by both adults for approximately 28 days.

It seems incongruous that flying birds would burrow underground to build their nest, instead of taking to trees. One of our more interesting fishing birds has evolved to build its nest very close to its food source.

The belted kingfisher is a joy to watch as it dives head first into a lake, pond, stream or river to retrieve a small fish. I have heard its rattling call many times when paddling our rivers and will usually hear its call as it zooms past me heading downstream. It stops on a river bank tree, eyeing me carefully until the current brings my canoe closer to its perch, and then it flies again downstream, as if leading me down river. One more stop at a tree and it flies at top speed in a straight line back up river – happy that it has successfully escorted me away from its nest.

Along a sharp curve in the river, where years and force of moving water have cut a steep bank into the hillside soil, sand and gravel, the kingfisher has burrowed a slightly inclined tunnel of four feet in length, ending at a round cavity where five to seven white eggs are laid. Both male and female will incubate the eggs for 23 to 24 days. Their territory is a linear stretch of river of about 1,000 yards.

This is the time of year when we hear the forest drummer drumming. Woodpeckers of various species abound in our region’s woods, and the fast drumming we hear in spring is how they attract a mate or communicate with one already found. From the small downy to the large pileated, woodpeckers use their sharp chisel-like bills to search for ants and insects hidden inside the trunks of trees. It is also how they make nesting cavities for rearing their young.

There is nothing quite like seeing a pileated woodpecker. They are about the size of a crow, and their deep crimson red cap stands out as it flies through the woods in swooping motions. The male will select a tall, usually dead, tree and after several test taps to check the density of the wood, will select a softer, more rotted section and begin to chisel his way into the tree. It may take a week of work, but he’ll create a hole big enough for three to five white, almost round eggs. Both adults will incubate the eggs that will hatch after 15-18 days.

My guess is most readers have seen the cup nest of a robin in a nearby shrub or bush in their backyard. Perhaps you have a barn swallow who has taken up residence and built its mud-lined cup nest firmly attached to an overhead beam in your garage or porch.

The cup nest I have never had the pleasure of discovering is that of the ruby-throated hummingbird. The nest of a hummingbird is tiny – only an inch across and an inch deep — and made of the most remarkable materials, such as leaf bud scales bound together with spider web. The nest is lined with milkweed fluff and thistledown and is then covered with green and gray lichens bound with spiderweb and web of tent caterpillars. Inside the female lays two tiny white eggs the size of peas, which will hatch in 11-14 days.

I have already described the small nest of the red-eyed vireo I have dangling from my office bookcase. Dunning calls these pensile nests, which hang and are suspended from above. The beauty of the red-eyed vireo nest is its basket and hammock-like shape woven at the fork of a twig. The light weight of the red-eyed vireo nest allows it to be built at the ends of smaller exterior branches and twigs where most predators cannot go. The red-eyed vireo will lay two to four white eggs with tiny brown and black spots. Incubation is by the female and takes 12-14 days for the eggs to hatch.

The most unwelcome of birds is the parasitic cowbird, who doesn’t build a nest of its own, but instead lays a single egg in the nest of another bird, leaving the incubating and rearing to its unsuspecting host. Unfortunately for the host bird, the cowbird typically hatches before the host eggs and quickly outgrows its nest mates, beating them out for the available food. Their cowbird habits, while horrible to us humans, are a fascinating story of evolution and adaptation.

To find a pendulous nest in our region means you have discovered the nest of a Baltimore oriole. It is a woven pouch made of plant fibers, bark, bits of yarn and hair and lined with soft plant fiber. The one I discovered was hanging from the tip of a downward swinging branch high up in an elm tree. Inside would have been four to five white eggs with brown blotches. The female incubates the eggs for 12-14 days.

As May slides toward June and the Summer Equinox, I’ll listen for the Baltimore oriole. When I hear its distinctive “hew li” and rattled call, I’ll scan the green foliage for the flash of bright red-orange that heralds the arrival of summer.

Our region’s birds are a joy to observe and learning their habits is a life-long pursuit. Spring and summer is when we get to experience not only the year-round, four-season residents, but also our warm “nesting” season tenants as well.

I hope you’ll join me in the fields and forests. Let us tune our ears to the songs of the season and focus our eyes on the hidden places, where warm nests hold the eager promise of an egg.

Bill Reid is the chief ranger of The Last Green Valley National Heritage Corridor and has lived in the region for more than 35 years. He can be reached at bill@tlgv.org