- Johns Hopkins University
- Queen‘s University
Summary
Black-capped Chickadees (Parus atricapillus) sing a two-note tonal song that has stereotyped frequency parameters (glissando and frequency interval). We hand-reared and tutored pairs of nestlings in acoustic isolation to determine the extent that learning is involved in the production of these parameters. Each pair of birds was tutored with a high frequency fee-bee song, a low frequency fee-bee song, or a low frequency fee only. Song gradually developed from a warbling subsong to sustained, whistled notes. Individuals did not match the absolute frequency of their tutor songs and sang over as wide a range of frequencies as adult males do in the wild. Five of the 10 males incorporated some normal frequency parameters of the tutor songs into their own songs. None of the birds tutored with only fee sang with a normal frequency interval, even though they did sing songs with more than one note. Males tutored with each of the other two songs did learn to sing with the correct interval. Our results suggest that the structure of Black-capped Chickadee song is open to environmental influences and that chickadees may learn the relative frequency parameters of their song.
Methodology
We removed 21 Black-capped Chickadee nestlings from three nests at the Queen's Univ. Biological Station, Chaffey's Locks, Ontario on 8 June 1990 at 10 to 12 days after hatching (Environment Canada Permit EC0619). The day of removal is termed day 0, with respect to all other procedures reported here (normal fledging age is 16 days). The nestlings were grouped by clutch and reared following procedures and diet adapted from Lanyon (1979). We determined the sex of the birds after the experiment by laparotomy, and only vocalizations from males were analyzed.