So far the fall of 2012 has been the best in years in the northeast US for irruptive finch species from the north. This weekend I recorded the flight calls of three of these species at Pennypack Trust in Huntingdon Valley, Pa, just north of Philadelphia. The first two, Common Redpoll and White-winged Crossbill, have "tchet" calls that can easily be confused when, as with these flyover birds, they aren't giving other flight calls, (the redpoll also gives a trill, the crossbill a House Finch-like vheet). Fortunately, the sonagrams are very different.
Common Redpoll
White-winged Crossbill
This distant Red Crossbill was a type 3, the most likely type in this part of the country. The call is quite distinctive, it sounds a little like a Tree Swallow.
Red Crossbill calls are at 3-4kHz
The chance of detecting these birds is far greater by listening for their calls as they fly overhead than by finding them feeding in their favorite trees. Recordings help confirm their identification, and are especially helpful in the case of the Red Crossbills, which have at least ten call types.
Birds of the World Online previously The Birds of North America Online (BNA). Comprehensive information on all aspects of life history, including audio and video. By subscription.
Birdsong by the Seasons. Donald Kroodsma, Houghton Mifflin, 2009. Another great book with CDs from Dr Kroodsma.
Flight Calls of Migratory Birds WR Evans and M O'Brien. CD-ROM www.oldbird.org. Excellent source of information on flight calls
Nature's Music, The Science of Birdsong. Peter Marler and Hans Slabbekoorn. Elsevier Academic press. 2004. A treasure trove of information, advanced but very readable (comes with CD).
Peterson Field Guide to Bird Sounds of Eastern North America. Nathan Pieplow, 2017. Highly recommended, includes almost all known vocalizations of eastern US birds, with spectrograms and detailed analysis. Excellent!
Stokes Field Guide to Bird Song, Eastern Region, by Lang Elliot. 3 CDs. Of commercial recordings, this has the most comprehensive collection of songs and calls.
The Singing Life of Birds. Donald Kroodsma, Houghton Mifflin, 2005. Terrific book (plus CD), a must read.
The Songs of Wildbirds. Lang Elliott., Houghton Mifflin, 2005. Excellent photos with high quality recordings including some rare ones such as the flight song of the Western Meadowlark.
The Sound Approach to Birding. A guide to understanding bird sound. A. van de Berg, M Constantine, M. Robb. Superb discussion of bird calls and song with 2 CDs.
Red Crossbill calls are at 3-4kHz
No comments:
Post a Comment