Part 2: Michael’s Report of Mid-August – August 17-24
As avian parental care in Casco Bay is nearing an end and fall migration is on a roll. Some of our summer residents have already left Casco Bay. Our summer residents, who have not yet taken the plunge, will eventually leave. Many migrants are just passing through going south while others stop here to join our year-round steadfast residents - to slug it out with us during fall and winter on Peaks Island.
Weather affects bird migration. What about fog? What is ‘fall out’? Michael (1) was about to find out when he set out on a recent extremely foggy day in search of avian activity. Here is his account and below it, the results from his research on eBird, to answer his and our questions about fog and ‘fall out’. Also further below, Michael will share even more of his pursuits of the avian kind. And, as a bonus, Michelle and Butch, tell of us Northern Gannet sightings. Please read on:
“YES! Dense fog does cause fall out! This accounts for the very unusual experience I had yesterday morning (August 24th) where, in front of Battery Steele I saw 10-12 Ruby Crowned Kinglets in a single flock, very agitated, flicking their wings as they do – with the males showing their ruby crowns. In addition, male and female Nashville Warblers, Magnolia Warblers, Eastern Kingbirds, American Redstarts, Ruby-throated Hummingbirds, Black and White Warblers were observed - none of which I had seen before while birding this August in the same location. So, I believe I experienced a small ‘fall out’ yesterday.
When I went back on August 25, I found none of these birds after four hours of searching, and getting soaking wet in the fog, light rain, and humidity. The highlight, however, was a Least Sandpiper flying along Backshore, and both Alder (first recording for PILP registry) and Willow Flycatchers in front of Battery Steele. (1)”
So, Michael, what is ‘fall out’? ‘Fall out’ is a sudden weather-induced cessation of migration. Here is what he found out about ‘fog-induced fall out’:
Fall Weather Conditions: “Weather is one of the chief external influences on migration. Cool air masses moving south in the fall can trigger migratory flight. Cool air brings high pressure, low or falling temperatures and winds moving in the direction of flight and clear skies. If the cool air meets warmer air, clouds, precipitation and fog may result. Fog, especially, causes birds to descend to the ground and cease migration. Sudden changes in the weather can be disastrous for birds.” (2)
Michael’s keen eye for finding those little birds in the bushes, and his endless patience as he searches for hours, wet with sweat and dripping fog, is an asset – he is a Peaks Island’s eye in the bush, and the shore. Even before this big ‘fall out’, Michael devoted endless hours in mid August tracking birds – spotting many fall migrants. The ‘double-icings on the cake’ were his observations on August 17 of a pair of Yellow-throated Vireos near Battery Steele, and of four Black-legged Kittiwakes (a small gull) and a Sooty Shearwater (related to the albatross) on the Backshore, He would have missed the kittiwakes, if it had not been for one, seen flying overhead on its way to join the other three about 75 yards offshore. These three species are the first recorded PILP sightings. (1)
Black-legged Kittiwake, Cape St. Mary's, NFLD
The Sooty Shearwater is a trans-equatorial migrant in both oceans – and is in a sort of reverse migration. This bird is probably returning to its breeding grounds in the Falkland Islands or Chile – although it is unusual to find it in the NW Atlantic at this time, as the prevailing winds take it to Europe in late summer, on its way down to the Falkland Islands or Chile breeding grounds. (3)
On this same day Michelle and Butch reported that, while sailing, they discover a flock of Northern Gannets fishing around East Cod Ledge ~ 8 miles from PI: “It was very impressive as they dove like a bullet into the waves for fish. Wow, what a sight!” These elegant seabirds have started their oversea migrations southward from their northern breeding grounds (e.g. Bird Rock @ Cape St. Mary, Newfoundland; Northern Gannet Species Account) where both gannets and the kittiwakes share the cliff nest sites. Michael refers to gannet diving maneuvers as “kamikaze”. Weather conditions affect gannet migrations: they are frequently blown close to shore during nor’easters. Keep your peepers open for such an event this fall. (October 2014 Bird Blog)
For size comparison: Northern Gannet and Black-legged Kittiwake, Cape St. Marys, NFLD
Michael continues his search that day and after 4.5 hours he sees 30 species, including a Yellow-bellied Flycatcher – another new species for the PILP bird registry. He notices that song sparrows are now in very short supply – ‘just saw six immature birds, hearing no songs’. As noted in the July blog, tree swallows are mostly gone; he sees just two, out over the water on Backshore. Michael runs into Biff and Grace at the Brackett Ave marshes: they saw a Glossy Ibis, a Great Blue Heron, and bitterns as well as the Black-crowned Night Herons. He sees only a single night heron. (1) (Also, please see Shay’s video of the Glossy Ibis posted on the August 19 PI Neighbor.)
Glossy Ibis, Beaver Pond
Juvenile Black-crowned Night Heron, Beaver Pond
On August 23rd, at Brackett Ave marshes Michael sees a Solitary Sandpiper. The eight Black Ducks were all accounted-for on Brackett Pond, and he saw Brown Thrasher only once this month. The Red-wing Black Birds have all but left; there are no swallows; Cedar Waxwings remain; there are Gray Catbirds everywhere; and the Common Eiders (females and young) are increasing in numbers again. An intense, yet elegant, aerial display between a Cooper’s Hawk and one of the young Common Ravens was quickly glimpsed – a two minute pursuit of the larger raven (24 inches long; 53 inch-wing span; and 2.6 pounds) by the smaller hawk (16.5 inches long; 31 inch-wing span; and 1 pound). Fortunately to no avail, as the shaken raven’s newly acquired flight skills out maneuvered the hawk’s keen flight agilities. (1, 4)
“Now, a story for the ages: A couple on a golf cart stopped to chat with me on Brackett Ave and asked where they might have dinner. I recommended The Cockeyed Gull. “Is that a real bird?” the man asked. This one goes into the same folder with “Where is the bridge to the mainland?” and “Where do I buy tickets to the ferry to get back to Portland?" (1)
Summary of late July through August Bird Activity
Below are birds seen from late July through August and listed in groups according to their current whereabouts.
1. Birds still encouraging their young to leave the nest:
Osprey, Herring and Great Black-backed Gulls, Black Guillemot (?) and Barn Swallow
2. Our breeding birds that are mostly gone:
Black-crowned Night Heron, Glossy Ibis, flycatchers, vireos, Tree Swallow, Brown Thrasher, warblers, Song Sparrow, Red-winged Blackbird (Note that the juvenile Common Ravens have left the island to join other juvenile ravens - in 'raven gangs')
3. Summer resident birds that will leave this fall and winter, depending on their food source availability:
Double Crested Cormorant, Great Blue Heron, Snowy Egret, Mallard, Osprey, Cooper’s Hawk, Spotted Sandpiper, some Herring and Great Black-backed Gulls, Common Tern, Ruby-throated Hummingbird, Eastern Kingbird, Barn Swallow, Gray Catbird, warblers, Song Sparrow, Red-winged Blackbird
4. Migratory birds seen as they pass through Casco Bay:
5. Winter resident birds returning from the North to spend the winter here:
Common Loon, Bonaparte’s and Ring-billed Gulls (The sea ducks and grebes will soon return to the waters off PI.)
6. Year round resident birds: Common Eiders, Black Ducks, Bald Eagle, some Herring and Great Black-backed Gulls, Black Guillemots, Common Ravens, American Crows, Titmouse, Black-capped Chickadee, Cedar Waxwing, Cardinal
7. The Sooty Shearwater who breeds in the Southern Hemisphere during our winter, will be heading South too.