Reports are coming in now of migrating Red Crossbills, especially in northern Wisconsin. This species is famous for wandering widely to find good cone crops and it seems like many are currently headed east through our area.
Red Crossbill occurs in a variety of “types”, which may be subspecies but some have argued are actually cryptic species. Type 9 was recently promoted to full species status as Cassia Crossbill (a very interesting long read on that type here).
What’s the best way to find Red Crossbills?
Listen! Often people detect these birds by hearing their call notes as a flock flies overhead. The call notes vary by type but are often described as “kip – kip – kip”.
Here is a sample of some Type 2 crossbill flight calls (crossbills start 5 seconds in).
Which types occur in Wisconsin? (We need your help to learn more!)
As far as we know, Type 2 and 10 are among the most common and probably our main breeders. But Types 1, 3, 4, and 5 appear to be possible. The 2012–2013 Red Crossbill irruption in Wisconsin (map) we think was mainly Type 3 birds.
This article by Matt Young has a good synopsis of the types and some samples of recordings: http://ebird.org/content/ebird/news/recrtype/
Here are maps of the current Red Crossbills reported to eBird (with audio).
Type 1 map – No records in eBird for WI (yet)
Type 2 map – We think this type is a regular breeder in the north
Type 3 map – Many of these are from the 2012–2013 irruption – but a breeding flock in Portage Co. could have been this type (Type 3 confirmed in that area in late April, RECR confirmed there in early June)
Type 4 map – Note Ryan Brady’s recent find – and zoom out to see how few eastern records we have recently. Apparently the last major Type 4 irruption was 1969–1970?
Type 5 map – A Ryan Brady recording also just furnished the first known state record, and the second east of the Mississippi.
Type 10 map – We think this type is a regular breeder in the north
And don’t forget Red Crossbills can be early breeders, so if we do have an irruption, the birds moving in this fall and winter could be producing young by early next spring.
Wisconsin Breeding Bird Atlas map – Types 2 and 10 confirmed breeding so far, will this irruption bring others?
How can you tell the types apart?
You need to obtain a recording of their flight calls. But you don’t need a fancy expensive microphone, anything that can record audio or video will work, including a smartphone. So remember to have your phone, camera, or audio recording device at the ready! You may only have about 15 seconds to get your device out and get a recording if they are flying overhead. The good news is that even poor quality recordings are often good enough to type.
Send the recording or video to Matt Young (firstname.lastname@example.org) and he’ll identify it. Then upload the recording to your eBird checklist to help us track crossbills. You can do this by using the “media” button near the species comment field. Remember that right now eBird does not take accept video uploads, only audio, so you have to convert it (or have Matt convert it) to an audio format like mp3 or wav.
Keep your ears out!
Thanks to Matt Young for help on this article (and for identifying dozens of our recordings!)