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SHARP-SHIN REVISITED

Purple Finches have been more than abundant at Hilton Pond Center during the winter of 2003-2004. In fact, just this week on 1 March we banded 39 of these winter seed-eaters, followed by 27 the next day, and 32 on the 3rd. Numbers dropped drastically on 4 March with only eight finches captured, and the 5th brought only nine. On 6 March we caught just four Purple Finches, and none on the 7th. Undoubtedly some of this precipitous decrease resulted from several balmy days with temperatures in the upper 70s. In additon is is usually about now that most Purple Finches leave the Carolinas for breeding grounds in the northestern U.S. and southern Canada. We suspect there was one additional factor that may have caused the sudden bailout: The presence of a Sharp-shinned Hawk in late morning on 4 March. We've written before about sharpies at the Center (see 15-21 October 2000), but the behavior--and apparent impact--of this newly arrived avian predator makes the topic worth revisiting.

All text & photos © Hilton Pond Center

At dawn on 4 March we were actually 60 miles north of Hilton Pond, checking out a reported winter hummingbird in Hickory NC. After hanging around a homeowner's feeder until 9:30 a.m. and never seeing the hummer, we decided it probably--like the Purple Finches--had already started a migratory flight to its breeding grounds. We returned to York SC and the Center at about 10:25 a.m. and quickly set and baited all our bird traps, including one that hangs outside the main observation window of the Center's old farmhouse. This particular trap, box-like and made of 1/2" x 1" welded wire, contains a sturdy Droll Yankee tube feeder filled with black sunflower seeds. Small songbirds enter the trap through any of several "tunnels" with tiny doors that swing in. Once inside the trap, the birds consume all the seeds they want but are unable to exit because the doors don't swing out. In winter it's not uncommon to capture ten or more finches in this trap within just a few minutes, after which we open a side access door and remove them for banding.

As soon as this trap was set on 4 March, we went back inside the office to check E-mail. When we made the first trap check ten minutes later, we already had caught eight new Purple Finches and three American Goldfinches, all of which which we banded and released. Every ten minutes or so we looked out the observation window to see if additional finches had entered the traps but noticed there were essentially no birds to be seen--a real change from the preceding two months in which scores of Purple Finches, House Finches, American Goldfinches, White-throated Sparrows, Blue Jays, Tufted Titmice, and Carolina Chickadees had swarmed around our various traps and feeders.

Just before noon we saw that two brown Purple Finches had entered the hanging tunnel trap but were sitting perfectly still--usually an indication some predator was in the vicinity. Sure enough, perched on an old cedar snag only ten feet from the trap was a Sharp-shinned Hawk, Accipiter striatus. Fortunately, our camera--fitted with a 400mm lens--was close at hand, so we grabbed it and through the double-paned glass door got off a quick and dirty photo of the hawk (top). In an instant, the sharpie exploded from its perch; our next exposure (below) shows the bird making a powerful downstroke with its wings while its long thin toes still tightly grip the branch.

Another second later the hawk was flapping wildly around the hanging tunnel trap--even latching onto it with its talons--all the while trying to get at two undoubtedly terrified Purple Finches. After a couple more digital exposures, we opened the side door of the farmhouse, distracting the sharpie. Not to be deterred from a possible lunch, the hawk simply dropped down to the edge of a small water garden beneath the trap and alternately stared at us and its intended prey (bottom photo). Since young sharpies have yellow eyes and vertical brown streaks on their breasts and older adults have deep red irises with horizontal rusty breast bars, we suspect this orange-eyed hawk at Hilton Pond was a subadult--perhaps in its third year.

We walked slowly out onto the side deck and, amazingly, were able to get within 15 feet of the hawk before it took flight into a nearby tree. As we removed the two Purple Finches from the trap, the still-hungry sharp-shin probably decided we were too close for comfort and sailed up and over the treetops to the north, eventually flying out of sight. The finches--both of which were already banded--appeared none the worse for their near-death experience, so we jotted down their band numbers, released them, and watched as they flew off toward a dense stand of Eastern Red Cedars.

Even though it was only noon when the hawk episode occurred, we caught no more Purple Finches before dark, and only banded nine the following day. Again, these numbers were well below the norm for the preceding two months and may indeed have been a function of the warm weather and some internal clock that told the finches it was time to go back north. We can't help but wonder, however, if the presence of a hungry, hyperactive Sharp-shinned Hawk around Hilton Pond Center wasn't so powerful a stimulus that it sent our once-plentiful Purple Finches speeding northward--or at least to some other less-hazardous feeding station.

All text & photos © Hilton Pond Center

NOTE: Be sure to scroll down for an account of all birds banded or recaptured during the week, as well as some other interesting nature notes.