Well folks, it is getting to be that time. The exquisite weather that we have enjoyed for most of the past summer has made bird watching a real treat, but there is no guarantee that it will last forever. October can be a stormy month and the fact that many of us are restricted to weekend forays only means that a couple of rainy weekends can wipe out any chance of early-autumn birding. The majority of warblers will be gone by the time this column reaches you, so I wanted to take this chance to close out the summer with a final farewell to one of the most reliable warbler species that lives in my meadow.
The common yellowthroat (Geothlypis trichas) is a species that shows up early in springtime and lingers late into the last moments of the summer. Fortunately, this species is also really easy to detect when it arrives because the adult males are in full song and ready to roll. There is no good way to describe the distinctly “birdy” noises this species makes, but the rhythm of the male’s song does seem to conform to the syllables in the phrase, “yellowthroat-yellowthroat-yellowthroat.”
Another helpful characteristic is the fact that the adult males have dark black “Lone Ranger” masks that cover their eyes and a patch of very bright yellow feathers on the chin and throat (hence the species’ name). Females are a more subdued yellow-brown that might fall into the Dijon mustard shade, but even they have throats that are noticeably brighter yellow than the rest of their feathers. Together, a pair of adult common yellowthroats can fill the meadow with activity. Even better, there is never just one pair, so feuding couples can produce a lot of excitement.
If you have been reading my columns for the entire month of September, then you will almost certainly have picked up on the fact that warblers tend to have a somewhat generic natural history. The adult males do a tremendous amount of singing to attract mates and establish territories. The adult females make the rounds and do their best to select the most impressive males that they can find. Once a pair has made a commitment, there will be a round of mating and then the female will get to work on a nest.
Most warblers construct “cup” nests that are exactly what comes to the minds of most people when they hear “bird nest.” These are single-use structures that go up quickly and only have to last for about a month. The female common yellowthroat is solely responsible for building the nest, which is constructed of weeds, grasses, bark and sometimes even bits of ferns. Then the inside of the cup is lined with finer plant materials and made ready for a clutch of three to five white eggs that are decorated with brown spots and smudges. The female can only lay one egg per day, so she will not visit the nest except to deposit an egg. Only when the final egg is laid will she start the incubation process, which takes about two weeks.
After the eggs hatch, the male will pitch in with the delivery of food. Common Yellowthroats prefer overgrown fields (like my wet meadow), hedgerows, and forest edges and in such habitats there is usually plenty of food; so much that the common yellowthroat is often able to complete two broods of offspring in a single breeding season. Proof of the success of the breeding efforts of my resident couples is easy to see because immature common yellowthroats are everywhere.
Better than simply being numerous, the youngsters are also extremely curious little creatures. Every day I go down to my thinking chair I am sure to become the object of some intensely curious scrutiny by several young birds that appear to have missed the migration memo. The adults have all but disappeared, leaving their offspring to fend for themselves. It is still warm enough to support plenty of insects and spiders in the tall grasses of the meadow and dense undergrowth at its margins, so the little birds are fine. Soon, however, even they will take the hint and they will be gone for another year.
The northern edge of this species’ winter range follows a line that stretches from coastal North Carolina to the easternmost portions of Texas. Wintering birds may continue on to Mexico, all of Central America and all of the Caribbean. The winter migration is a tricky time for these tiny little birds and they are utterly dependent on finding habitat along the way where they can find something to eat and rest a little. So imagine the astounding life of the oldest recorded common yellowthroat that was captured during banding efforts in our very own state of Massachusetts. The bird was 11 years and 6 months old when it was released back into the wild. How many thousands of miles did it fly in its lifetime?
Bill Danielson has been a professional writer and nature photographer for 28 years. He has worked for the National Park Service, the US Forest Service, the Nature Conservancy and the Massachusetts State Parks and he currently teaches high school biology and physics. For more information visit his website at www.speakingofnature.com, or go to Speaking of Nature on Facebook.