by Laramie Aspegren
One of the great privileges of living in a tropical country is the near constant presence of nesting birds. Due to the lack of well-defined seasons, many birds nest throughout the year. One of my favorites is the Rufous-tailed Hummingbird, which nests in my yard for most of the year. With a little keen observation and a lot of patience, their tiny nests aren’t too hard to find, and then they can be observed and studied until the hatchlings fledge.
Rufous-tailed Hummingbird is by far the most common hummingbirds in Costa Rica. It is quite vocal for a hummingbird, and often fights. It also prefers disturbed habitats, like gardens, yards, and secondary growth, which are coincidentally what many humans prefer, as well. On top of all that, Rufous-tailed will also eagerly visit hummingbird feeders and many different types of flowers. All these factors combined makes Rufous-tailed Hummingbird conspicuous and well known to the general population.
Rufous-tailed Hummingbird is medium-sized hummers, about 4.5 inches from beak to tip of tail. To put it in perspective, it is a bit larger than Ruby-throated or Broad-tailed hummingbird. On the top, it is pretty drab - its black-tipped, coral red bill protrudes from an overall greenish upper body. The wings are charcoal colored; the belly is light gray. The tail, however, is the real attraction of this hummingbird. The bright rufous tail outlined in black shines like fire every time the sun catches it. In bad light, the green and gray parts of Rufous-tailed turn black, but never the tail.
Female Rufous-tailed Hummingbirds are entirely responsible for nest building and incubation. They build tiny cup nests on thin, forked branches. The cup itself is constructed out of woven grasses, plant fibers, and spider webs, and then coated on the inside with down. The outside is often completely covered in lichens and mosses, which are just for show. (Rufous-taileds are quite the exterior decorators.) From my measurements of abandoned nests, their nests usually measure 3.5-4.5 centimeters wide and 2-3 centimeters tall. Preferring the cover of the undergrowth, most Rufous-taileds nest somewhere between 1 and 4 meters off the ground.
Once nest building is complete, the female layers the bed of the nest with down and lays two white eggs. Incubation usually takes 2-2.5 weeks, during which time the female is almost constantly present around the nest. After hatching, the chicks grow and live in the nest for about three weeks, until they fledge. Even after fledging, the family tends to stay in the vicinity of the nest during the day.
For a couple months last fall, I had a family of Rufous-tailed Hummingbirds living in a tree next to my driveway. I found the nest by watching a Rufous-tailed collect cobwebs from a tree outside my window and following her back to her nest. I showed my family the nest, and then we followed her progress throughout the next month, every time we drove in and out of our front gate. My family and I watched them grow from tiny chicks to maturing chicks in an amazingly short period of time. Unfortunately, we missed their actual fledging, although we continued to see them in the next couple weeks, first only in the trees around their nest tree, then more and more into the yard, until they separated completely and took their own path in the world. Overall, it was an awesome experience.
About the author: Laramie Aspegren, 16, is a young birder currently residing in San José, Costa Rica, where he has been birding for the past couple of years. Along with his dad, he loves traveling around Costa Rica in search of interesting birds and exotic places. Out of all the wonderful birds of Costa Rica, his favorite are the Typical Antbirds, for their unique songs and flashy plumages. Laramie attended the 2011 ABA Camp Colorado.