PIBO Migration Summary

May 11th – 20th, 2012



Black-billed Cuckoo


Migration activity at the Point was steady but not overwhelming from the 11th – 20th, due largely to the fine weather throughout the summary period. As a result, migrants encountered good flight conditions and no large fall-outs were recorded, although there were no especially quiet days either. In all, ten spring ‘firsts’ were recorded compared to 46 during the first ten days of the month, and 202 birds of forty-one species were captured in 488 net-hours, for an average catch-rate of 41 birds/100 net-hours. By comparison, 452 individuals of fifty-one species were banded in 437 net-hours (103 birds/100 net-hours) from May 1st – 10th. Diversity at the station ranged from a low of 53 species recorded on May 20th during PIBO’s official count period to a high of 66 species noted on the 14th.


Northwest winds and a dawn temperature of 12° C on May 11th made for a fairly active day, with 57 species tallied, including fourteen warbler species and the first ‘Traill’s’ Flycatcher of the spring, along with an Iceland Gull. A similar morning on the 12th produced 59 species, 15 warblers spp., and the first Blackpolls of the year. Once again, the 13th was a near mirror image of the previous two days – 60 species were recorded including 14 warbler spp. and a slight increase in thrushes and flycatchers. May 14th was the most active morning of the summary period, with 66 species documented on the day (17 warbler spp.). Although just fourteen birds were banded, they included the second Worm-eating Warbler banded this spring, along with a male Blue-winged Warbler. 


Another similar day on the 15th was followed by some intense thunderstorms on May 16th that limited field coverage to the census and a few hours of mist netting. There were still lots of birds around, however, with 59 species detected in 2.5 hours of monitoring. Diversity tapered off on the 17th and 18th and there was little to report apart from the first Yellow-bellied Flycatchers of the spring, a noticeable increase of Canada and Wilson’s Warblers, along with ones-and-twos of a nice variety of species including Yellow and Black-billed Cuckoo, Ruby-throated Hummingbird, Wood and Swainson’s Thrush, and Scarlet Tanager, among others.


The final two days of the coverage period saw an increase in activity both on the census and in the netting area, with 73 birds captured over two days and 61 species noted on the 19th, including the season’s first Acadian Flycatcher (banded). A captured female Hooded Warbler on May 20th was one of 53 species recorded on the day.


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


Photo: Sumiko Onishi