Wednesday, August 1, 2012

Red Crossbill type determined

Red Crossbill (type 2), Prescott Peninsula, MA, July 30, 2012


video

Red Crossbill (type 2) video, Prescott Peninsula, MA, July 30, 2012

As a follow up to my reports on Red Crossbills on the Prescott Peninsula at Quabbin the specific type has now been determined.   The specific type of Red Crossbill has been determined to be type 2.  This was determined with the assistance of Ian Davies who converted the video, with its associated audio, into a wave file and then used the Cornell Lab of Ornithology’s free software (Raven Lite) which can be downloaded from this link:
The recordings I obtained were compared to those of the different known types of Red Crossbills using a spectrogram.  The determination of type was obtained in this fashion.  Type 2 Red Crossbills occur across a large area of the country including the northeast.  Other types have/could occur in this area. There are at least nine (or ten) recognized types of Red Crossbill.  The overall size of the bird and the bill varies with each type but determining all types by sight alone is difficult to impossible.  The only way sure way to differentiate the types is through calls viewed as a spectrograph.

Additional information concerning these various types and their associated calls can be found at the following link:
http://ebird.org/content/ebird/news/introduction-to%20crossbill-vocalizations


As with previous sightings of Red Crossbills in this area breeding is suspected (and has been confirmed in the past).  The first Red Crossbills on Prescott Peninsula were noted on June 3, 2009 and small numbers were seen through the end of the year in 2009.   The largest number seen on any one day during that year was 14.   In 2010 they were first noted in April and seen through early July.  The largest number seen on a single day in that year was 26.  During the other years of the breeding bird atlas they were not noted.  Juvenile birds with adults feeding them were noted in both 2009 and 2010.  Also during 2010 they were noted in Quabbin Park in the same area from mid October through the end of November with the greatest number seen being 14.  A great overview of breeding in the state can be found on the Massachusetts Breeding Bird Atlas page found at the following link:
http://massaudubonblogs.typepad.com/massbirdatlas/2010/11/218-red-crossbill.html

To sum up the above mentioned link the number of breeding Red Crossbills is quite small in the state with the only confirmed records during the entire five year long atlas study occurring at Quabbin, specifically on the Prescott Peninsula.  The other probable location for breeding in the state was also at Quabbin, located in Quabbin Park.  The only block with possible breeding was located in Plymouth County.  Certainly one of the rarer breeding species in the state with only a handful of confirmed records.  It does appear that the Prescott Peninsula is a breeding hotspot for this species in Massachusetts.   

SUMMARY (These results last updated 01 Aug 2012):
Red Crossbill
Blocks
All
Confirmed
3  
Probable
1  
Possible
1  
Observed
1  
Blocks with evidence ¹
5  

Chart above courtesy of Mass Audubon and the Massachusetts Breeding Bird Atlas.

For a little bit more information the range maps of various types can be found at the following link:


With the permission of the staff at Quabbin I hope to continue additional research on this species on the Prescott Peninsula in the coming years.

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