Winter bunting banding in southern Ontario is determineded by a simple mathematical formula: Sn + Brr = SNBU (HOLA, LALO)
Sn – Snow
Brr – cold temperatures
SNBU – SNow BUnting
HOLA – HOrned LArk
LALO – LApland LOngspur
Starting yesterday afternoon the temperature began to drop into the minuses and a light snow started falling. By this morning it was -5 C and there was an accumulation of ~7 cm of snow. So I ventured out early to my York Airport site on the edge of Regional Road 9 to validate the formula. Sure enough there was a flock of ~ 25 Horned Larks on the snow-covered bait piles that I had set out a couple of days ago. It was interesting to me that, although the gravel pad used by farmers to load wagons with soybeans harvested from the field was about 150 square meters, the birds were confined to the immediate area of the covered piles. I hadn’t topped up the piles for awhile since I hadn’t seen any birds feeding on them (and I check twice daily) and they didn’t appear to have been touched. But as soon as the conditions got tough the birds “knew” exactly where to forage. Had they stored this information in their memory banks?
When you first set out traps the birds are fairly wary; they fly into the trap area in small flocks and scoot around them picking at any corn pieces they can get to through the mesh. But one bird was different: it didn’t fool around; no checking things out; saw the food and went right into the trap. It was the Lapland Longspur pictured above. And this has been my general experience with this bird over the years – we catch and band at least several each Winter as “by-catch” to the Snow Buntings. They seem to figure out very quickly how to get at the bait by navigating the access tunnels. It just seems apparent to them; they don’t wander around and around until they chance into a tunnel – they simply go for it. There was just one though and once it was banded it left the area.
The flock of larks would tease me – fly in, circle around, fly off 50 meters and think things over, fly in again, circle around….
Every now and again they would fly off completely and then return 10 minutes or so later…or was it the same group? Hard to tell as I would get anywhere from 8 up to 45 birds in the trap area at various times. But I didn’t see any Snow Buntings. So after banding 3 birds (1 Longspur, 2 larks) my strategy to prepare for the coming days (as it is supposed to stay cold) was to remove the traps and replenish the cut corn piles so the birds could feed unfettered for the rest of the day and would thus likely be back tomorrow…and the day after….
So I pulled the traps. Immediately, as if on cue, a flock of 40+ Horned Larks and 60+ Snow Buntings flew right to the bait. I unpacked everything and put the traps out again. The buntings flew to the end of the field and then disappeared. But the larks, after initially flying off, returned and soon I had another 10 to band – a mix of both males and females. When I was finished I decided to take up the traps and revert to the above strategy. If the larks continue to feed (and they were on the bait as I pulled out), the buntings will be back – they’re very cognisant of where other ground-feeding birds are finding food. Tomorrow could be a good day (especially if I dress warmer).