PIBO Migration Summary

September 11th – 20th, 2012


Magnolia Warbler


Migration activity was up-and-down at the Point from September 11th – 20th. It was relatively busy on most days with the exception of the 19th, when a meagre twelve species were recorded thanks to some intense rainfall and gale conditions throughout the morning hours. The busiest day was on the 16th when 50 species were tallied during the official count period and 75 birds of fifteen species were banded, for an average catch-rate of 1.25 birds/net-hour. In all, 85 species were documented in the count area from the 11th – 20th compared to 92 from September 1st – 10th, and 271 birds of twenty-five species were captured in 372 net-hours, for an average catch-rate of 0.73 birds/net-hour. Twelve fall ‘firsts’ were noted.


During the previous summary period, 461 individuals of thirty-one species were banded (1.0 birds/net-hour), along with eight ‘firsts’.  Catharus thrushes (especially Swainson’s and Gray-cheeked Thrushes) continued to dominate at the nets, with 187 individuals of three species banded over ten days. To date, 572 thrushes have been captured this fall from August 1st to September 20th, including 422 Swainson’s Thrushes.


It was moderately active during the first four days of the coverage period, although strong southwest winds and warm conditions (20° C at dawn) didn’t provide much incentive for migrants to move south. An average of 32 species was noted each day from the 11th – 14th and 81 birds were captured. The transition from typical August and early-September migrants to late-fall species was evident with the arrival of the first Yellow-bellied Sapsuckers (September 11th), Ruby-crowned Kinglets (12th), and White-throated Sparrows (14th), along with Peregrine Falcon (11th) and Broad-winged Hawk (12th).


The wind shifted to the north on the evening of September 14th, which produced a busier morning on the 15th. Fifty-three birds of twelve species were banded and 50 species were documented, including the first Brown Creeper and Purple Finches of the season. Eleven warbler species were observed on the day. Although no new arrivals were noted, September 16th was also active, with 75 birds banded and 50 species tallied during the count period. Thrushes were numerous , with 50 birds captured, along with good numbers of warblers (15 species observed and 8 species banded). A nice variety of other species included Black-bellied Plover, Belted Kingfisher, Philadelphia Vireo, Winter Wren, and Northern Parula, among others.


Although thrushes continued to move through on September 17th, including 21 Swainson’s (18 banded), 7 Gray-cheeks (7 banded), and a banded Veery, it was noticeably quieter compared to the previous day. A Lesser Yellowlegs was noted at the tip along with 6 Bald Eagles, and eight warblers species were observed in small numbers. The 18th was a total washout – no banding took place due to the rain and gale-force west winds, and just twelve species were tallied on the census, which probably represents a 10-year station low. To put it in perspective, a grand total of 15 individual songbirds were detected in 90 minutes, and five of them were Northern Cardinals!


Conditions improved the next morning, with 46 species recorded on the census on September 19th including fall ‘firsts’ for Northern Harrier, Yellow-throated Vireo, and a male hatch-year Hooded Warbler. Fourteen warbler species were tallied along with a range of other birds including 4000 cormorants, 7 Bald Eagles, some Sanderlings, 3 Blue-headed Vireos, a Northern Parula, 3 Rose-breasted Grosbeaks, and a lingering Indigo Bunting. A captured Sharp-shinned Hawk proved to be a foreign encounter that was originally banded at White Fish Point at the northern tip of the Michigan Peninsula in May 2011. Strong south winds on the final day of the summary period made for a relatively uneventful day apart from a female Peregrine Falcon buzzing around at the tip.


PIBO’s next migration summary will be posted on October 2nd.


Photo: Sumiko Onishi