Birds : August heat
Changes in the ambient temperature and weather patterns, accompanied by the now noticeable and quickly decreasing length of day, the photoperiod, are the catalyst for bird migration. Every day at this season, regardless of weather conditions, there will be migration - some birds will move. However, with the passage of any kind of frontal system or weather pattern, many more birds will move than when the weather is settled. It is important to get out in the field as often as one can in the upcoming weeks, because really no two days are alike.
This adult common tern has just missed a fish in a headlong plunge and is climbing back into the air for another attempt. Photo by E. Vernon Laux Yellow warblers are gathering in small migratory groups and are calling outside my window while I'm writing this. The weather has started to change dramatically and for birders in the northeast, and especially on the coast, this is the time of year that we wait for. The months of August, September, and October offer some of the finest birding anywhere in the world, right here.
In fact, late August and the first half of September are the best and only time to see many scarce species on the Cape and Islands. The upcoming weeks provide the best opportunity to see many scarce and rare shorebirds. A Eurasian shorebird that has only been seen a handful of times on the Vineyard was discovered in the fields at The Farm Institute on July 25. This species is rare, but regular in North America. It remained on the Island for only a couple of days.
All shorebirds are strong flying birds and many breed in the far north and winter at the southern tip of South America. These scarce long distance migrants include Hudsonian godwits as well as Baird's and buff-breasted sandpipers. Arctic-nesting species are rare, but regular during a small window at the end of this month. During the spring migration these birds move north through the middle of the continent, as do most adults in the fall. But with predominant northwest winds in the fall, small numbers of immature birds may appear, making their first southbound migration.
Although the aforementioned species may appear, they are by no means a sure thing. They often are not seen or detected at all and may go unrecorded for several years in our area. Historically, the best time to encounter these globetrotters is on or around Labor Day weekend.
Tern numbers are impressive at many favored spots. This is a great opportunity to study the wide variety of plumages that these birds exhibit. A couple of hours spent looking carefully at a flock of terns is fun and educational. Adult terns can be seen in all plumages from breeding adult to winter adult. The adult soft parts, bill, and leg color change from bright reddish orange to black, the black cap molting from solid black to white forehead - black remains only on the top and back of the head and shoulders. Then there are the immature birds molting from fresh juvenile plumage to first winter. It is a great time to note the differences between common and roseate terns.
Terns are fascinating and are only here for only a short while longer. While watching a flock of terns attempting to sort out the various plumages, pay close attention to the
birds' behavior. You will see an adult approaching a mixed flock with a fish in its beak. This adult will only feed its own chick that it locates by sound. The bird will fly over the entire flock calling and the young birds will call back, hoping for a meal. It may make several passes and generally it creates a bit of mayhem amongst the hungry youngsters.
Not only are the beaches and tide flats loaded with birds now, but on certain days so are most woodlands and thickets. Those of you who feed birds or do a lot of gardening might want to consider providing water in the form of a birdbath. Birds are attracted to water for drinking and bathing more in this season than at other times.
If you make the water move by creating a little drip action it makes it easier for birds to find. A little electric bubbler, a tilted watering can, or any other way to make a little movement makes it exponentially easier for thirsty migrant land birds to find.
With land bird migration about to hit full speed ahead, providing moving water will alert day-tripper birds to its presence. It can be very exciting and surprising to note all the different kinds of warblers, vireos, and other visiting birds that will drop in for a quick drink and a bath.
Until next time - keep your eyes to the sky.
