We went into May with high hopes. Coming off a record April. the future looked bright indeed. But then the wheels came off….and they never seemed to get back on.
I like the simple stat: “birds per 100 net hours”. One net hour refers to one 12-m net open for 1 hour; the stat is the number of birds caught for every 100 hours a net is open. It gives a rough calculation of the flow of birds through the site. Always….ALWAYS…the number of birds per 100 net hours at Ruthven in May is larger than the number for April. Always. But not this year. For the first time in 18 Spring seasons, the rate of flow for May was lower than it was for April (20.2 birds per 100 net hours vs 26.4). This deflation caused our overall season statistic to nosedive so that we experienced the lowest rate (22.7/100 nt hrs) in our 18 Spring seasons.
The drop was most noticeable in the number of warblers we caught: normally they make up about 21% of our Spring catch but this year accounted for only 15%. And when you take Yellow Warblers and Common Yellowthroats (since they nest here) and Myrtle Warblers (a short-distance migrant) out of the mix, this drops to only 7%. Neotropical migrant warblers made up only 7% of our banded birds!? Yikes! We had many days this May when the forest was simply empty. No warbler song or movement. We thought it strange….strange and ominous at the same time. And it still is unsettling. It will be interesting to see what other stations experienced; whether this was simply an anomaly specific to our station this year, or something that was witnessed over a broader range.
For the record:
– we banded 1,793 birds
– 883 in April; 910 in May
– we banded 82 species
– on our “biggest” day we banded 62 birds (April 8th & 14th)
– over the two months we saw 151 species, the most interesting being a Clay-coloured Sparrow and an Olive-sided Flycatcher
American Goldfinch – 288
Golden-crowned Kinglet – 145
Dark-eyed Junco – 115
Yellow Warbler – 106
Chipping Sparrow – 99
Song Sparrow – 86
Gray Catbird – 74
White-throated Sparrow – 73
Brown-headed Cowbird – 73
Ruby-crowned Kinglet – 62
On a positive note, we had 1,170 visitors in April and May and volunteers contributed 1,263 hours of their time to make it all happen.
Thanks to everyone! Numbers really don’t account for the fun that we had and the learning that we experienced.