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May 11, 2006  Hauling Grass During spring many birds do what they miraculously know how to do - build nests. I assume this skill is instinct-based because birds do not receive instructions, and a nestling would not be paying much attention to the structure in which it spends the first few weeks of life. Yet, without hesitation and when the timing is right, all bird species undertake nest construction. Some birds, such as Ravens and Grey Jays, nest early. For most bird species, the beginning of May is the signal to haul grass, collect feathers, hair, moss, lichens, cattails, rush stems, and the myriad of materials that go into the construction of various nest types. Nests are as varied as bird species. Nighthawk nests are little more than depressions scraped on bare ground while the nests of Orioles and Vireos are elaborate hanging affairs that appear to require a degree in architectural engineering. A Hummingbird nest is a marvel of art. It consists of spider webs, lichens, the fluff of willow catkins, and cattails stuck to a horizontal limb. So resilient, watertight and wind resistant are the eggcup sized nests that when the sides of an empty nest are flattened, they can bounce back to regain their original cup shape. The Cliff Swallow carries mud pellets from nearby puddles, then hangs upside down under the eaves of a building to construct an igloo-shaped nest. Swallow nests can hold the combined weight of the Swallow parents and up to four nestlings. With all the comings and goings of the parent birds, some Cliff Swallow nests do fall, but many stay in place all winter. A few weeks ago Kingfishers arrived in the Cariboo. One particular pair that I enjoy watching claimed their traditional large mud cliff along the creek and immediately began nest building. Kingfishers tunnel into a mud or sand face to a depth of about 6 feet, not an easy task for any bird. I have only once witnessed Kingfishers tunneling. After entering the hole, the Kingfisher sat with its tail sticking out and used its bill to chop away at the compacted tunnel material. Somehow these fish catching birds use their small feet and short legs to kick an incredible amount of sand out of a very long passage. Once the tunnel length meets their requirements the female deposits the eggs on the bare floor of the chamber. Fish bones and other debris will build up by the nestling but the plain floor of the tunnel requires no further embellishments. One of the nests I discovered this year was a real surprise. I spotted it on May 1st with a Robin already in it. This nest was used last year and built on top of the handles of a number of hockey sticks stored in the rafters of the wood shed. I guess this particular Robin wanted to get the jump on the first clutch of eggs by eschewing the whole nest building process and simply jumping into a ready made. To check that the nest really held a clutch of familiar Robins-egg blue eggs, I removed the rear view mirror from a vehicle in the yard, taped it to a stick, and slowly raised it to nest level. The Robin and I had a peaceful relationship until she spotted the mirror approaching, then she flew off quietly. After I counted the four eggs and moved away the robin flew back to the nest and resumed incubating. Other Robins, not as inclined to find or use an old nest in good repair are only now beginning to construct their own nests. Today, at the marsh, I saw a Coot towing long strands of cattails into a secluded spot in the reeds. This took place while two nearby broods of Canada Geese floated about with goslings in tow. Obviously Geese were incubating eggs in the middle of April. It's a good thing a Goose nest consists of a lot of Goose down for insulation! Other Canada Geese at the marsh are still sitting on eggs. I like to encourage Hummingbirds to the yard by supplying them with a few old fluffy cattail stalks. The females hover around the choice nesting material, pull tufts of it off, then buzz away in a bee-line to their nest site. Since a young age, I have always been captivated by nest building birds. Every spring my brother and I made it our goal to find all the bird nests in town. We spent hours finding the nests of Killdeer, Spotted Sandpipers, Brewer's Blackbirds, Song Sparrows, Nighthawks, Goldfinches, Yellow Warblers, Red-eyed Vireos, Ravens, Robins, and many other birds. I recall a particular Brewer's Blackbird that flummoxed us practically right in our own back yard. It scolded us and flew over us as we searched a small group of spruce trees, none taller than six feet, so we knew it nested there. It should have been easy to find, but try as we might we were unable to spot the nest. In the fall we speculated that perhaps the bird was toying with us and really had no nest. Later, we discovered the beautifully constructed hidden structure about four feet up in one of the prickly spruce trees. Like most things in life, the one that gets away lives on in the memory more vividly than the one that is found. To e-mail Tom CLICK HERE To look at previous column CLICK HERE |
