Weekly Reports

On July 30, 2023, the Lesser Slave Lake Bird Observatory concluded the second of our four core monitoring projects: Monitoring Avian Productivity and Survivorship (MAPS), which focuses on breeding birds. With Spring Migration Monitoring a distant memory, all that is left is to continue our Fall Migration Monitoring until October, and to wait for Northern Saw-whet and Boreal Owl Banding to begin in September.

Although we ended well shy of the record of 862 birds banded in 2021, and even shy of last year’s 610 bands, this year’s MAPS banding total was still double the average of 289 birds per season with 546 birds banded. This dip in bands may be due to the last period of MAPS capturing relatively few birds. In fact, for some of our stations, this past run was the slowest this year. Normally we expect to be inundated with migrants by late July, but we were surprised to frequently find empty nets. This low migration activity has also kept our Migration Station slow with just a trickle of overhead flights where normally we are entering our first peak in southward songbird migration.

Above: Total number of birds banded during MAPS per year since we began running all four of our current stations with a three year moving average. The red diamond represents 2023’s preliminary total which is still well above average, but lower than the past two years.

When we band birds in the fall, the most important information we collect is the species followed closely by how old we estimate the bird to be – whether hatched this year or last – since this data is almost impossible to collect without having the bird in your hand. Yet, ratios of young to old birds in the fall may be used to suggest if our songbirds were unable to raise large families, and this may have been one such year.

While there are certainly recently hatched birds moving through, it seems as though there are relatively few. Often this time of year sees the nets filled with young birds with the older generation making up a relatively small portion of our captures. If this trend continues through the fall, it is likely that there was a problem in North-western Canada resulting in few young leaving their natal grounds. It is too early for us to suggest a cause for this peculiarity when we do not yet have enough data to be confident that it even exists, but we are eager to investigate this observation once Fall Monitoring has concluded.

Above: Purple Finch have already beat their previous banding record for MAPS and are on their way to beating their previous fall record as well with 7 banded, creeping up on the current record of 11 in the fall of 2015.

Despite what may have been an unproductive year for our birds, no species saw record low MAPS captures. Alder Flycatchers and Philadelphia Vireos edged out their previous record high band totals by a single bird each, Purple Finch broke their previous record of two banded in 2009 with six banded, and Swainson’s Thrush beat out 82 banded in 2021 with 116 banded.

Likewise, it was a record-breaking year for capture diversity with 36 species banded – well above the MAPS average of 26 species per year. Capture highlights included our seventh through ninth Pine Siskins, fourth and fifth American Three-toed Woodpeckers, fourth White-breasted Nuthatch, second Yellow-shafted Flicker, and first three White-winged Crossbills ever banded since we began MAPS contributions in 1994.

Want to learn more in person? Call the Boreal Centre for Bird Conservation and ask about our Bird Observatory Tours taking place most Wednesdays and Saturdays through August.

By Robyn Perkins, LSLBO Bander-in-Charge

Preliminary total number of birds banded during MAPS, 2023 in order of most captured to least: