Potsdam, NY (St. Lawrence County)
For the past 4 out of 5 winters at our home in Potsdam, we've had a Northern Shrike spend the season behind our home along Plum Brook (an area with open fields, wet shrublands, deciduous forest, marshes, the brook, and plenty of hawthorn trees). In the morning on October 29, 2009, I stepped outside on our back porch and heard a Northern Shrike vocalizing. It was at the top of a deciduous tree near the marsh, but in a location where I would not have noticed the shrike had it not been vocalizing. As I watched the shrike, Amer. Robins were drawn in - flying around the tree and perching below the shrike. Each time the robins perched, the shrike would loudly call and dive at them. The robins took off each time, but continued to come back (loudly calling). I watched the same behavior over and over - the shrike singing/calling, the robins flying into the tree, the shrike calling loudly as it dove at the robins. The only change occurred when a Rusty Blackbird joined the robins just once. (The Rusty Blackbirds could be heard vocalizing in the nearby marsh.) Eventually, I got cold and left the birds to their antagonistic behavior. In the morning on Nov. 1, the Northern Shrike was observed perched in several locations (top of deciduous trees and top of shrubs) and in pursuit of a Blue Jay (not successful). At dawn (6:45 a.m.) on Nov. 4, I went outside on the back porch and found the Northern Shrike vocalizing - an enormous barrage of interesting vocalizations. I'm an ear birder, so I was in heaven, and wished I'd had recording equipment at that moment. The vocalizations drew a Blue Jay to the shrike. Each time the shrike flew at the Blue Jay it made a very loud call - as it did with the robins on Oct. 29. After a few attempts at catching the Blue Jay, the shrike gave up and flew across the large field - but loudly called just before it flew. Today, Nov. 7, at dawn, I spotted the shrike at the top of a deciduous tree behind our home from my bed! (This particular tree seems to be the favored Northern Shrike perch in winter, and I can see it from my bed.) I ran downstairs and outside, but the shrike was gone. I listened and heard a distant shrike vocalization coming from across the large field, and then a robin began calling from the same location. I found some interesting information on Northern Shrikes vocalizing outside the breeding season in The Birds of North America Northern Shrike account under "Sounds - Vocalizations": ***Frequency and function of winter singing cause of much speculation ( <http://bna.birds.cornell.edu/bna/species/671/articles/species/671/biblio/bi b017> Bent 1950, <http://bna.birds.cornell.edu/bna/species/671/articles/species/671/biblio/bi b038> Cramp and Perrins 1993). Since fifteenth century (Barnes 1486, Boke of St. Albans), some writers have stated that shrike imitates calls and songs of other birds to lure them into vulnerable range of attack: "She will stand at perch upon some tree or poste, and there make an exceedingly lamentable crye and exclamation, such as birds are wonte to do, being wronged or in hazard of mischiefe, and all to make other fowles to thinke that she is very much distressed and stands in need of ayde; whereupon the credulous sellie birds do flocke together at her call. If any happen to approach neare her, she out of hand ceazeth on them, and devoureth them (ungrateful subtill fowle) in requital for their simplicity" (seventeenth-century author in <http://bna.birds.cornell.edu/bna/species/671/articles/species/671/biblio/bi b079> McCowan 1951: 171-175). Atkinson ( <http://bna.birds.cornell.edu/bna/species/671/articles/species/671/biblio/bi b012> 1997) showed experimentally that playback of recorded shrike songs in winter attracted other small passerine species to significantly greater extent (quicker, closer, more frequent approaches) than playback of American Robin song or control playback of background tape noise; he observed 4 instances of shrikes using such opportunities to attack other birds, twice successfully. Whether potential prey are attracted to mimicked versions of their own songs and calls ( <http://bna.birds.cornell.edu/bna/species/671/articles/species/671/biblio/bi b092> Munro 1911), to generalized predator distress or alarm sounds incorporated into shrike songs, or to the oddity of various, juxtaposed warbles, gurgles, squeaks, and squawks (analogous to human "squeaking" to attract birds) remains to be determined, but songbirds appeared most responsive to portion of shrike song that incorporated jaa calls (EAC).*** If this particular Northern Shrike continues to sing/call through the winter, I'll be thrilled! Other recent observations: Ruffed Grouse and Pileated Woodpecker have been observed each day. 11/7/09 Dark-eyed Junco - still moving through Red-winged Blackbird & Common Grackle flocks flying over (occasional grackles at our feeder) 11/6/09 (first snow in Potsdam) Amer. Tree Sparrow - 1; first of the season 11/2/09 Golden-crowned Kinglet - migrant Fox Sparrow 11/1/09 This was the last day of large Amer. Robin flocks (now there are smaller numbers still around). 10/26/09 Ruby-crowned Kinglet - last day observed Fox Sparrow Purple Finch - last flock heard going over (this species was moving around the North Country in Oct.) 10/23/09 Great Horned Owl vocalizing (2 a.m. and 6:20 a.m.) White-throated Sparrow - last day observed 10/21/09 Hermit Thrush - last day observed Song Sparrow - last day observed White-crowned Sparrow - last day observed This year, there were large Amer. Robin flocks feeding on the berries of Gray Dogwood and (invasive) Buckthorn (among all the sparrow species passing through). It appears that they favored the Gray Dogwood berries, and they are just about cleaned out. There are still plenty of Buckthorn berries available, which seem to attract thousands of Bohemian Waxwings to this area in winter. As Matt Young recently pointed out, the Bohemian Waxwings are showing up each year. Since I have only observed them eating buckthorn berries in winter (in this area), I wonder if they frequented this location before Buckthorn was brought over from Europe? Joan Collins Potsdam & Long Lake -- NYSbirds-L List Info: http://www.NortheastBirding.com/NYSbirdsWELCOME http://www.NortheastBirding.com/NYSbirdsRULES Archives: 1) http://www.mail-archive.com/nysbirds-l@cornell.edu/maillist.html 2) http://birdingonthe.net/mailinglists/NYSB.html Please submit your observations to eBird: http://ebird.org/content/ebird/ --
