Naturalist Journal: Questions from the Mailbox

Dr. Chuck Welsh answers listeners' questions about skunks, hummingbirds, sparrows and snakes in this installment of the Naturalist Journal.

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Host: Someone wants to know if skunks mate in the fall or spring?

Welsh: Like most local mammals they mate in the spring. Mating occurs in Feb. and March with young born in May.

Host: Well, several folks have inquired about hummingbirds. Seems that that there are two popular questions: when do hummingbirds arrive back in town, and how do they know when its time.

Welsh: This is actually the time of year we will start to see them return anytime from mid-late april. The earliest I recall seeing one was about April 20th at my feeder. Migration is a complex behavior but it is initiated by the length of the daylight. Longer days stimulate hormone production which then causes a cascade of migratory and mating behaviors. In the fall they know its time to leave because the days become shorter.

Host: Is the migratory trip for hummingbirds non-stop or are there lay-overs?

Welsh: That's a good question. There are lay-overs. In fact, the timing of their migratory behavior has evolved to coincide with the flowering of plants along the route. That way they can stop and fuel up.

Host: Seems that male birds get all the vocal glory, some folks would like to know if female chickadees also sing?

Welsh: In songbirds the call is the vocalization used all year by both sexes and the song is used by males for territory defense and mate attraction. Females chickadees do not sing, but female cardinals have been known to.

Host: Well song sparrows are certainly in full singing mode by this time of year. A few listeners were wondering why some of these sparrows have slightly different songs.

Welsh: Song sparrows exhibit geographic dialects. That is, the birds in western pa sound more like each other than any one of them would sound like one from the mid-west. The further you go the more the song changes even if only slightly. Some of the differences we can hear but others the birds can hear but we cannot. And we only know that there is difference because of making a graphic read out called a sonogram.

Host: This next question I understand you are asked quite a bit. Sparrows and finches look like little brown cardinals, is this resemblance a coincidence?

Welsh: Great question. The resemblance is not at all coincidental. They are all part of the carduline finch family. All of these birds have thick, robust, cone-shaped bills that are built to crack open seeds.

Host: And finally, you know, many people fear snakes and are wondering are they active yet?

Welsh: Oh yes they are. My sons and I have found several garter snakes in the past week and I have seen a few already smashed on the roads on my bike rides. They are now coming out of a state of torpor and their metabolism is speeding up and they are hungry.

Host: Do you have recordings?

Welsh: Yes I do. I have a song sparrow.

Have questions for Our Intrepid Naturalist? Write or call him at 412-536-1174.