Take a deep breath, it’s over for now. Birders can relax as all the birds have finished their northward spring migration and have settled into their breeding territories, some here, and many others much further north. But believe or not, the fall southbound migration of shorebirds begins the first of July so our respite will be short-lived.
Of the 10,000+ species of birds only 40% are migratory, the others seemingly content year-long residents of their chosen habitat. Of those that migrate, each species has a different strategy; long vs. short distance, daylight vs. nighttime, early spring vs. later, overland vs. overwater, and short hop vs. long haul. Each strategy has advantages and short-comings. For example, flying at night when it is cooler saves energy and avoids predators, while daytime flying allows feeding on insects cut during flight and navigation over recognized land masses. I thought it might be interesting to look at a few migrating birds I photographed this spring and tell their migration story.
The orange and black blur streaking through the trees at Magee Marsh last week was usually not a Blackburnian Warbler, but much more likely the larger Baltimore Oriole. In any other setting a birder would rejoice at the chance of observing and photographing the gorgeous oriole, but at Magee Marsh they suffered from overexposure–it was one of the most common birds there. This tropical appearing bird is exactly that, a bird of the tropics spending most of the year migrating or wintering in Mexico, Central America, or Columbia, and only 4 months of the year in our temperate breeding zone. Given this, it’s a bit presumptuous to name it a “Baltimore” Oriole, but being from Maryland I’ll live with it.
I took a day this week to check out the migrating shorebirds along the western shore of Delaware Bay. There were thousands feeding a long scope-distance away on the jetty across the harbor, with Ruddy Turnstones being the most numerous and good number of Red Knots and peeps mixed in. I’m sure you’ve heard the Red Knot story of their long trek from the tidal flats of Patagonia, up the S. American coast, and the 7000 mile flight over ocean, bringing them to Delaware Bay just in time to feast on the trillions of Horseshoe Crab eggs. See my blog dated 5/30/2015 “Spring Migration II: The Red Knots vs. The Horseshoe Crabs” for more details. But their rest stop in Delaware is just temporary with many miles to go before reaching their breeding grounds in Canada.
I also stopped off at Slaughter Beach. The name seems appropriate. I was there at low tide and the shorebirds were feeding far away on the tidal flats. The beach above the high water mark was littered with thousands of overturned horseshoe crabs, likely upset by the surf as they were trying to lay or fertilize eggs. From the smell I thought they were all dead but after kicking one over he or she started crawling down the beach toward open water. So I tried another, and another, and so on, with perhaps half still living and saved by me for another season. But there were thousands. When do I stop turning them over? Finally I did stop but could not help wondering what the very next crab thought of me as I turned away and left him to his fate upside down.
The Ruddy Turnstone shares in the feast on Delaware Bay but due to its shorter migration route is not as dependent on the crab eggs. Turnstones can be found all winter along the Atlantic coast from New England to S. America and I see them frequently on the Florida coast in their non-breeding attire, (they are rarely found inland). But seeing them in their spectacular spring plumage is a real treat. They’ll soon be heading to their breeding grounds on the far northern coastal tundra of Canada and Alaska.
The Black-billed Cuckoo is a specie of concern due to declining numbers. Its breeding territory is the eastern U.S. and southern Canada and migrates over the Gulf of Mexico in fall, wintering in northern South America. I was happy to stumble across this difficult and stealthy bird, just off the trail near the visitor’s center at Magee Marsh, while scanning the underbrush for thrushes and low-foraging warblers. He or she may have chosen the marsh as a breeding location, but more likely it was part of the throng of birds waiting for an opportune wind before crossing Lake Eire.
The Blackpoll Warbler, despite its lack of dramatic color, is the superstar of warbler migration. Its breeding ground is the furthest north of all warblers, in western Alaska and stretching across the continent to Labrador and northern New England. And its wintering territory is the furthest south of any warbler in the western Amazon and rainforests of S. America. The bird I photographed at Magee Marsh was only halfway through its spring journey north, perhaps heading to Alaska. In the fall even the birds far west in Alaska decline the straight route south and instead fly eastward to New England and then turn right, following the east coast of North America, the Caribbean, and open ocean before arriving exhausted in S. America, thousands of miles later.
So as we settle down observing our familiar nesting and resident birds, we have again been refreshed by the less common spring sojourners and marvel at their semiannual feats on the wing. You won’t want to miss Act II this fall.