Sunday, August 16, 2015

All Change

Though the beach-going tourists flocking to Cape May right now might think that it's high summer, the birdwatching calendar has most decidedly turned the corner into fall, and mid-August marks two classic fall events for Cape May birders - the Maurice River Purple Martin spectacle and the start of CMBO's Morning Flight count at Higbee Dike. Ashamed as I am to admit it, I had not previously witnessed the post-breeding gathering of Purple Martins on the Maurice River before this weekend, so volunteering with my wife to help on the river cruise, organized by Citizens United to Protect the Maurice River aboard the Bodacious seemed the ideal thing to do.

Purple Martins are nothing if not sociable, and gathering in large flocks is typical behavior for them outside of the breeding season. As with many species of birds that employ communal roosting behavior, Purple Martin roosts tend to occur at traditional locations and large numbers can build up over a period of years. Provided the sites are left unaltered and are considered safe by the birds, such traditional roosts may be used for very many years and older sites can attract very high numbers of birds. The roost on the Maurice River has, in recent years, moved around a little, but has generally been centered on dense stands of Common Reed a little north of the Rt 670 bridge at Mauricetown. Though the roost is visible most years (though sometimes distant) from the bridge itself, little can compare with the experience of being out on a boat on the river while tens of thousands of birds swirl around, chortling overhead. The roost is generally in evidence at this location throughout most of August, so if you have not yet made the pilgrimage, then I suggest you contact Citizens United and see if you can get yourself on a boat trip. Be warned though, these trips are very popular and there may well already be a waiting list.

Purple Martins swarm above the heads of their admirers on the Maurice River last night [photos by Mike Crewe].

As if the dynamism and excitement of rushing hordes of pre-roost Purple Martins was not enough of a buzz, the trip up river also allows for some excellent Bald Eagle watching - we saw at least six different birds - as well as the ubiquitous Ospreys and assorted migratory waterbirds. Swirling against a pink-stained sky as the sun sets low to the west, the Purple Martins produce a wonderful sight, but the gatherings mark the end of another breeding season for them and the roost will gradually fall in number as parties of birds head south to winter mostly in Brazil, where they will remain highly gregarious throughout the northern winter. Much has been learned about Purple Martin through the efforts of a variety of scientific research programs and the collective data of the Purple Martin Conservation Association and its affiliates, but we still don't know all that much about the make-up of these post-breeding roosts; how long does an individual bird remain in the roost before heading south? Are individual birds site-faithful to a single roost or do they move around from night to night - or year to year? There's still so much to learn about these intriguing birds.

And so to the second of our mid-August landmarks - the Morning Flight count. This year's count kicked off a little quietly, it is fair to say, and I am sure many birders looked at the weather forecast the night before and thought "You know what? I think I'm going to have a lie in". For migration is nothing if not weather dependent and this morning's weather was clearly not going to be dropping scores of drift migrants onto Cape May. However, scientific data needs to follow strict protocols, and the start date is predetermined by previous year's protocols. So it was that a small but faithful band - including Glen Davis, the 2015 Morning Flight official counter, and Tom Reed, swing counter and count co-ordinator, among others, climbed the slippery slope onto the dike and at precisely 5:59AM, we all looked aloft and counted... well, not much at first. But this is science, and if there's nothing to count, that needs to be recorded too. Eventually, something of a trickle came our way and the 2015 count was well and truly started. But things were not the same this year; for a brief period (until it broke!) a chair made an unprecedented appearance on the dike, but far more importantly, a tablet, containing a spanking new computer program made its inaugural appearance. Yes, 2015 sees the introduction of a new way of logging and storing data for the CMBO seasonal counts which will mean a lot less time spent inputting data from paper sheets in the future. Even more importantly for onlookers, however, is the fact that you can now go online and see how the counts are coming along - almost in real time! This facility will be available right through the season for Morning Flight, the Hawkwatch and the Avalon Seawatch, so do check out the site once we go live (very soon!) - it's the next best thing to being here!

As well as being generously sponsored for another year by Swarovski Optik, this year the CMBO counts are assisted by product and computer programming from Specteo, a company that offers computer logistics in the field for collecting, storing and reviewing scientific data.

Small but select describes this morning's Morning Flight watchers. Higbee Dike is a remarkable place to be during fall, offering opportunities to watch not only the intriguing phenomenon of the morning flight itself, but also the comings and goings of a wide range of both land and waterbirds [photo by Mike Crewe].

Two screen shots of the new data presentation now available of the CMBO counts through Specteo. Data is updated every two minutes, so presentations are almost in real time - check back regularly to see how the season develops for our three seasonal counts. Morning Flight started today, the Hawkwatch starts September 1st and the Avalon Seawatch starts September 22nd.

Though day one of the 2015 Morning Flight was relatively quiet, there were some stalwarts to keep us interested. Indigo Buntings are present throughout much of the count period and seem to have a very protracted migration. At the start of the season, blue males can still be seen, but these will later be replaced by drab brown juveniles [photo by Mike Crewe].

You might be surprised to learn that even common 'resident' species such as Northern Mockingbird pass through and head south in the fall. But even these species take part in seasonal movements to a greater or lesser degree and many early birds on the move will be juveniles that are not so much migrating as dispersing away from natal areas. Note the dark flecking on the body of this bird which marks it out as a juvenile - a party of seven passed the dike at one point this morning [photo by Mike Crewe].

This is Cape May, so don't forget there's plenty of options for birding in other areas beside Higbee Dike. This adult Sandwich Tern and its fledged youngster were at Cape May Point State Park briefly this morning before beach traffic pushed them off. Hopefully they may stay in the area for a few days. At this time of year 'pairs' of terns on the beaches typically consist of an adult and a youngster rather than two adults [photo by Mike Crewe].

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