The endless fascination of birds and how they fashion their nests – Mad River Union

Nest art by Louise Bacon-Ogden

I n my last column, I discussed birdhouses. My intent was to also talk about nests.

I realized that nests needed a whole column devoted to them.

Birds are all over the world and vary from tiny hummingbirds to huge ostriches. As varied as the birds are the nests they build (or don’t). It is dependent on the bird and their habitat. The materials they use reflect where they nest.

Most think of bird nests in trees. Some nest high while others nest low. Some species use exposed tree roots to nestle a brood of chicks. While others choose the very top of big trees.

Nest cavities are sought after for safety. These are often created by woodpeckers yet a chickadee can excavate, too. As tree limbs die or are torn off in inclement weather, they, too, create cavities. In the desert, cavities are often made in large saguaros.

These cavities are often used as is, with debris from the excavation. Others are lined with nesting material which can consist of tiny twigs, cattail fluff, leaves, rootlets, pine needles or anything else a bird deems good construction material.

 

Many cavity nesters lay white eggs. Open cup nests usually have mottled or speckled eggs to disguise them. Many nests are made in trees or brush are not shaped like a cup. The oriole and bushtit make a hanging “basket.” These are usually suspended at the end of long supple branches.

Different birds choose different parts of a tree to nest. Besides the hanging basket, birds build nests on horizontal branches, in a fork, under loose bark or in a stump.

The marbled murrelet, a seabird, use a large horizontal branch of a redwood or other large tree. The bird makes a scrape in the moss for its one egg.

A magpie will build on a branch and then disguise the nest with twigs and thorny branches making a canopy-like structure above the nest. I love what marsh wrens do. The male claims a territory in a marshy cattail stand. Using the cattails as a support, he diligently gets to work on many nests, all within his territory. He can make four to seven incomplete or dummy nests about three feet above the water. Once completed, he will sing to attract a mate. These secretive birds are best seen during this period of their courtship.

 

An impressed female will chose the nest she deems suitable. She will then complete the structure begun by her mate. She will add cattail fluff, rootles and fine grasses. It is similar to a cup nest with a “roof” and a side entrance. She will commonly lay from three to six eggs.

Other marsh birds (bitterns, geese and ducks) may make a nest within the reeds or tall grasses, often on the ground.

Herons, egrets and sometimes cormorants nest in trees. They are also colony nesters. Often a colony may be of mixed birds. This group of birds creates a “rookery.”

There is a good-sized rookery off Hookton Road in the Loleta area. It can be seen from the Humboldt Bay National Wildlife Refuge. The rookery on Woodley Island may still be viable but it seems to be shrinking as some of the trees are dying.

In areas void of trees, birds may nest on the ground. On beaches, the snowy plover makes a slight hollow in the sand and rings the nest with small pieces of beach debris, like tiny pieces of driftwood, dried seaweed or pieces of shell. Eggs and chicks are speckled, matching their habitat.

Similarly, the killdeer makes a scrap in rocky pebbly dirt. It is more common near human habitation, so they may nest on a rocky rooftop or gravelly garden area. Again, eggs are speckled to camouflage them. To protect her nest, the female may feign injury to thwart off predators. The predator may think this injured bird will be an easy meal when she pretends to be hurt. And as the predator approaches, she can fly away from the nestlings.

Some birds dig or use burrows. The burrowing owl lives in open spaces of prairies or deserts. They can dig a hole or often prefer predug prairie dog holes. They line the nest with dried bits of horse or cow dung and possibly a bit of grass.

The American dipper will make a damp nest behind a waterfall. It is attached to a rock ledge and covered with live moss and small roots.

The barn and cliff swallows build mud nests. They transport mud in their beaks. It may take the couple up to eight or more days to build the nest, depending on the species. The nest could contain 1,000 mud pellets to complete the nest. Both swallow species are colony nesters. The difference between the nests is the shape. The barn swallow makes a cup nest (and often uses a barn) and the cliff swallow (the “cliff” they use is often the side of a building) makes a jug shaped nest. Their nests often touch each other.

I did a double-take when I saw a barn swallow nest “cellar” and the roof built by a cliff swallow. I guess that was a “fixer-upper!” It looked like it was a good choice as the cliff swallow peeked out at me.

Bird nests are so unique and diverse. For me, they hold a fascination and wonderment at the intricate structures they make to raise the next generation of birds.

In the Peterson Field Guide series, a book on Western Birds’ Nests by Hal Harrison has lots of information and over 30 pages of color photos of nests with eggs.