Got White-winged Crossbills?

White-winged Crossbills so far in 2008.

The early signs of this crossbill movement were already apparent in July, when hundreds were turning up throughout eastern Canada, Maine, the Adirondacks of New York, and elsewhere in northern New England. Stragglers in western Massachusetts and New York may have even been breeding.

As in past years, these summer movements were followed by big migratory pushes to the south. The above frequency chart from eBird for all of North America shows the influx starting in July and into August. As impressive as this movement was, what we are experiencing now is even more dramatic. If past years are a guide, White-winged Crossbills may be expected to show up this winter as far south as Virginia, Ohio, and Kansas, and stragglers may turn up even farther south to the Carolinas, Gulf Coast states, and northern Texas.

So this seems to be great winter for White-winged Crossbills. But how can you find them? As with most species, it helps if you know a little bit about the bird that you're looking for. While White-winged Crossbills do occasionally show up at bird feeders, you'll have much better chance of seeing them if you actively look for them. So far this winter reports have come largely from two types of locations--birds seen flying overhead at places generally conducive to watching bird migration and from conifers--particularly spruce, white pine and hemlock.

Extremely important is to develop a familiarity with White-winged Crossbill vocalizations. Crossbills (both Red and White-winged) are quite vocal when flying overhead and experienced birders detect them this way a majority of the time. White-winged Crossbill gives a chattering "tyet" call, usually doubled or tripled, and repeated once every second or two. A flock of crossbills can sound almost like static as they all call at once. While perched they may give other more musical calls. Red Crossbill, by contrast, gives a loud "jip" or "jip-jip" call, that it more distinct and less likely to run together. White-winged Crossbill flight calls are somewhat like louder, more twangy versions of a redpoll flight note. The Macaulay Library of Natural Sounds has a sound archive of 100 different recordings of White-winged Crossbill recordings that can be listened to online. From here you can also make comparisons to Red Crossbills, redpolls and a variety of other species.

Finding "migrating" crossbills

Over the next month we may expect White-winged Crossbills to continue moving south, even though most other migrants have largely stopped moving for the winter. If you know of areas that are good for migrating goldfinches, siskins, or other diurnal passerine flights, consider dressing warmly and spending a morning watching. To look for migrating crossbills, be sure to get out early. Most finch migration begins before dawn and extends to two or three hours after sunup. In the middle of the day the crossbills are unlikely to be moving around much.

On days with westerly or northwesterly winds, expect crossbills to be displaced offshore and to be found moving along the immediate beachfront or heading inland. Coastal migration sites like Lighthouse Point in Connecticut, the Long Island shoreline, Cape May, New Jersey, and Assateague Island (Maryland and Virginia) are some obvious choices but almost any vegetated beachfront could be productive. Along the Great Lakes, similar beachfront sites can expect large flights as well. Ridgetops (such as Hawk Mountain in Pennsylvania) that are good for migrating raptors can also be good for migrating finches, such as crossbills.

Finding feeding crossbills

It's usually much more rewarding to find crossbills that are feeding. This means you can watch them, and get a much better appreciation of them. To find them, pay attention to conifers with substantial cone crops. White-winged Crossbills have rather small bills and generally feed on conifers will smaller cones. Spruces and firs are most preferred so pay particular attention to areas with these species. In some areas, plantations of spruces have been planted which provide large blocks of habitat for crossbills. To the south, the local cemetery or arboretum may have plantings of non-native evergreens. Other species used by White-winged Crossbills include hemlock and Eastern White Pine--these species are probably more frequently used in the southern areas where spruces are much harder to come by.

As for migrants, getting out early is important. Whether migrating or feeding, in the morning crossbills fly around a lot and are quite vocal. By midday and afternoon they can be much more difficult to find. Listen intently for vocalizing crossbills and scan the cone-laden parts of the trees carefully for crossbills--when feeding they can be surprisingly tough to spot. While walking in conifer groves, be aware for flakes of cones filtering down from above, which can often be a clue that crossbills are feeding silently overhead. Also listen for the sound of crossbills feeding on conifer cones--at times this popping and snapping can sound almost like miniature fires in the tree tops.

Finding good locations on the internet

While you can read listservs and check eBird for locations to find eBird, nothing is quite as fun as going out and finding them in a new location. Google Earth and the satellite view on Google Maps can provide an excellent way to look for potential locations to find these winter finches. Consider exploring areas where we don't have data in eBird--you may be the first to find White-winged Crossbills in your county, or a neighboring county. The map below shows an area in Potter County, Pennsylvania that seems ideal for White-winged Crossbills. Typically, coniferous forests or conifer stands appear as dark green patches on these maps. As in the image below, they often stand out from the surrounding forest because they appear dense and dark.

Report crossbills to eBird . . . get your friends to . . . and those who post on regional birding lists!

We know that those of you reading this post are dedicated eBird users, who need no reminder to enter your sightings of something like White-winged Crossbill. But remember, even if you don't find White-winged Crossbills, please report those trips to eBird too. Negative data are every bit as important as positive data.

Please encourage birders in your area to report their crossbill sightings to eBird, whether they are friends of yours or regional birders that post to your local listserv. Posting to a regional listserv is a great way to alert others to sightings of crossbills in the area, but that record may not be archived in any permanent way and nor will it be organized with other crossbill sightings. Posting the record to eBird ensures that it will be permanently archived and accessible to you and others. We will use it for our maps and graphs too--if eBird can get all White-winged Crossbill sightings, we will be able to summarize the data as animated migration maps at the end of the season.

Last year's invasion of winter finches (particularly redpolls and Pine Grosbeaks) was probably documented better than any other invasion thanks to reports to eBird. The thousands of submissions documented both where the birds were and where they weren't (through submission of complete lists).Together let's try to document this year's White-winged Crossbill invasion even better!

Other winter invaders

Pine Siskin appears to be the other finch species on the move this winter. Most regions are experiencing elevated numbers of siskins, especially in comparison to last winter which was a "down" year for siskins in the East.

Most other "winter finches" seem to be experiencing a lackluster winter. Pine Grosbeaks and Evening Grosbeaks are not moving in large numbers, and Bohemian Waxwings seem not to be on the move much after last year's banner year. Surprisingly few Red Crossbills have been noted, even though some races of Red Crossbill have small bills and favor similar food sources as White-winged Crossbills. Boreal Chickadees have been noted moving in Canada and could occur south of their typical range this winter.

Finally, while they are unrelated to movements of finches, it is worth thinking about owls. Snowy Owls are turning up widely, with high numbers in New England and New York and reports as far south as Maryland (several) and Virginia. This may be the best winter in decades for Snowy Owls, at least in the East. Much more difficult to detect, Boreal Owls are on the move this winter and many have been banded at owl banding stations in Canada. Some have occurred as far south as Vermont and Maine already; although historically the species' southern limit has been New Jersey, Pennsylvania, New york, and Ohio, it is highly likely that vagrants occur much farther south and go undetected. This is the winter to try to get a first for Maryland, Kentucky, or Arkansas!

For more information on the biology of White-winged Crossbills or other irruptive species, check out the Birds of North America Online.