We finally got the long-anticipated cold front Saturday night, and woke up Sunday Oct 5 to slightly cooler temperatures and much lower humidity. A stiff NW wind was blowing and this direction is usually good for getting migrants to put down at Cape Florida. The radar that morning showed the heaviest flight yet of birds coming down the entire state, and we were pretty excited when we opened nets in the dark. Most of the night flight calls were Swainson’s thrush, and as the sun came up Western palm warblers began dropping down by the dozens and forming flocks in the palmetto scrub. We captured 19 palms in the first hour we were open, and then bird activity slowed down to nearly nothing.
Top: two Magnolia warblers. Bottom: Western palm warbler
We waited patiently and enjoyed the cooler weather but started noticing more and more birds around as the day wore on. By 1pm it was clear that new birds were arriving , and numbers and diversity increased, reaching a peak around 430pm or so. Some of these new arrivals found their way into our nets, and we ended with 89 new captures and one returning Ovenbird. Over half of these birds were caught between 1 and 5pm. American redstarts dominated this afternoon wave of migrants, but 15 species of warblers were seen or banded onsite.
Some of the new species for the season banded yesterday include this beautiful adult male Bay-breasted warbler (above). He still has the diagnostic bay coloring on his sides even though he is in fall plumage.
Another treat was this adult male Chestnut-sided warbler. He also is showing hints of his spring plumage, with the reddish sides and golden crown. The general color pattern is similar to the Bay-breasted, but they have different shapes and behaviors. The Bay-breasted is a larger, ‘sluggish’ warbler usually seen high in the canopy. The Chestnut-sided is slightly smaller, often forages in the midstory, and sometimes cocks its tail.
Scarlet tanagers came in at the same time. We saw several, and banded this hatch-year male (below). He can be aged by the jet-black shoulders contrasting with the brown wings; adult males are also yellow this time of year but keep the entirely glossy black wings and tail.
An interesting thing about the movement of birds on Oct 5 was that nearly all of these individuals of every species captured were very fat. Assuming they initiated their flight the night before right after sundown, these guys had been flying 18 -20 hours before arrival, and had hardly made a dent in their reserves! Perhaps they had not flown the entire night, but they still wanted to pause at Cape Florida before continuing on.
There was nearly a complete turnover of birds and a new species composition between Sunday Oct 5 and Monday Oct 6, when 62 birds of 17 species were banded. The birds that came in today were in the condition that would be more expected following a long but uneventful overnight flight, and they had moderately depleted fat reserves with flight muscles in good condition.
TOTALS Oct 5 & 6 2014:
90 birds of 18 species/ 62 birds of 17 species
American redstart: 20/1
Western palm warbler; 19/0
Black-throated blue warbler: 10/8
Common yellowthroat: 9/6
White-eyed vireo: 6/7
Magnolia warbler: 5/2
Black & white warbler: 5/2
Gray catbird: 4/12
Northern waterthrush: 2/3
Swainson’s thrush: 1/2
Ovenbird: 1/7
Northern parula: 1/0
Prairie warbler: 1/0
Yellow-billed cuckoo: 1/0
Chestnut-sided warbler: 1/0
Acadian flycatcher: 1/1
Hooded warbler: 1/1
Bay-breasted warbler: 1/0
Scarlet tanager: 1/0
Indigo bunting: 0/2
Swainson’s warbler: 0/1
Painted bunting: 0/4
Gray-cheeked thrush: 0/1
Common ground-dove: 0/2
Seen onsite but not banded: Tennessee warbler, Yellow-throated warbler, Red-eyed vireo, Yellow-throated vireo, Wood thrush, Mangrove cuckoo, probable Clay-colored sparrow.