National park travelers are keenly aware of the changing seasons. The Blue Ridge Parkway is a completely different experience in August than in October. The hoodoos of Bryce Canyon need to be seen both in the blistering July sun and the January snow to be fully appreciated. And, of course, there's Yellowstone ' a bustling city on a summer weekend and a tranquil white wilderness on a bright February morning.
Birders may be the one group of people more acutely tuned into the seasons than most travelers. One of the joys of birding is that there's always something new around the corner, on both the map and the calendar. If Vivaldi had written concertos about birding, he would have called them The Fourteen Seasons.
Take my home park of Sleeping Bear Dunes National Lakeshore as an example. This week, in the heat of what most tourists would call late summer, birders are enjoying early fall. The nesting pairs of endangered Great Lakes Piping Plovers have already returned to Florida and the Bahamas. Some of this year's hatchlings are still making their way south. The beaches are now occupied by migrating shorebirds returning from nests in the high arctic. Sandpipers, plovers, dowitchers, and maybe even a stray avocet will all pass through this month.
By the time the latest of the shorebirds, the Dunlin, stop by on their flight south, the songbirds will have begun moving through as well. Warblers, tanagers, vireos and flycatchers from the North Woods will be following the shoreline of Lake Michigan down to Indiana Dunes National Lakeshore, and then across the continent to the Gulf of Mexico. Songbird migration peaks sharply in September, and before you know it the waterfowl are arriving.
Diving ducks, grebes, and loons begin heading south in massive numbers once late September arrives. Tens of thousands of Red-breasted Mergansers will pass by the Manitou Islands of Sleeping Bear. This is when birders need to have a good spotting scope and the tenacity to stand on a wind-swept Lake Michigan bluff in October. The sight of a Red-throated Loon makes it worthwhile.
When weather begins to turn truly treacherous, the waterbird migration slows to a trickle heralding the arrival of rarity season. A rare vagrant bird can show up anywhere at any time, but in the east November is the best month for rarity treasure hunting. Western birds will be caught in strong winds and end up on the Great Lakes. Long distance migrants like Rufous Hummingbirds may even turn up at a late-hanging feeder long after the resident Ruby-throated Hummingbirds have moved on. Ancient Murrelets that should be floating in the Pacific Ocean off the beaches of Olympic National Park sometimes can been seen diving for fish in Lake Michigan. It's a time when the unexpected is expected.
As the end of the calendar year approaches, duck-watchers enjoy the spectacle of thousands of ducks on inland lakes and waterways. Many national wildlife refuges and game areas are closed to casual bird-watching in early winter to allow for safe duck hunting. This makes the national parks a great spot for safe and peaceful observation of ducks. Of course, this is all dependant on weather. It's not long after the Christmas Bird Counts are done that the inland lakes freeze over. Before the snow gets too deep in farm fields, this is a great time to see flocks of Lapland Longspurs and Snow Buntings foraging on their winter grounds. For them, Michigan is a tropical winter retreat.
In the depths of winter, Lake Michigan will often still provide good birding for the intrepid lakewatcher with well insulated clothing. In the winter of 2013-14 the lake froze nearly completely, making attempts to lake-watch futile. Diving waterfowl that typically winter far out in Lake Michigan were forced to congregate in any open water that could be found. Rivers became havens for Long-tailed Ducks, scoters, Horned Grebes, and Red-throated Loons. All of those birds are usually seen only at great distance on the big lakes, but last winter were easily seen almost at literal arms-length throughout the Midwest.
Winter is the longest birding season. From the time the inland lakes freeze until the end of February, about 8 weeks, birders are watching feeders for stray northern finches and other northern oddities. Some years will see irruptions of Common and Hoary Redpolls, Pine Grosbeaks, and Bohemian Waxwings. Other years the same birds can be completely absent, depending on food availability in the boreal forests. The main excitement this time of year is the potential for a vagrant arctic gull.
As March approaches, the first signs of spring migration appear. Male Red-winged Blackbirds arrive to scope out territory while the cattail marshes are still covered in snow. Birders are in the field daily, hoping to be the first to spot an Eastern Phoebe or Yellow-rumped Warbler for the region. Fox Sparrows are among the first migrants from their family. Killdeer are the first shorebirds to return to the north, well ahead of any of their cousins. While waiting for those arrivals, the winter residents begin to get edgy. Dark-eyed Juncos and American Tree Sparrows begin gathering in groups and fueling up for their impending trip north. Some of them even begin singing, no doubt practicing for the frenetic mating season in the north.
The migration dam shows signs of bursting as the calendar turns to April. White-crowned and White-throated Sparrows join the Fox Sparrows, early warblers begin to trickle in, and the first shorebirds that aren't Killdeer, the Lesser Yellowlegs and Pectoral Sandpipers, suddenly appear in flooded fields. Blue-headed Vireos will start flitting through the trees and kettles of Turkey Vultures fill the warming lakeshore skies. Keen observers may even spot a Golden Eagle among the raptors head north. Out on Lake Michigan the loons and grebes are slowly making their way back to their North Woods lakes.
During the first week of May the floodgates open. Two-dozen species of warbler move through along with several vireos, tanagers, sparrows, buntings, and every shorebird imaginable. This is Birding Christmas. Birding is fun all year, but in this region, the first three weeks of May is what we're really waiting for all year. A casual effort can yield a hundred species in one day.
It ends all too quickly. Summer arrives in late May when migrations slows suddenly to just a trickle. The summer residents are singing and building nests. Dabbling ducks occupy the ponds and lakes. Gulls abound on the Lake Michigan Shore and the Piping Plovers are back and setting up their beach nests.
After Canada Day and Independence Day have passed, the birdsong trails off. There's no more need to defend territory or attract mates. Some late nesters like American Goldfinches are still feeling vigorous, but for most summer residents, the hard work is done. The Piping Plover chicks grow rapidly. Biologists and volunteer plover monitors put color-coded bands on every chick so they can be traced by sight wherever they go. In August, the plovers have left and monitors in Florida will report back that a female who raised two chicks on North Maniotu Island in Sleeping Bear was spotted in Key Biscayne twenty-four hours after last being seen in Michigan. When it's time to leave for the fall, they don't waste time.
Once the plovers are gone, it's time once again to enjoy the influx of shorebirds that are already moving south. That's where we are today. Before you know it, the waterfowl will start moving. How long until May?
The chronicle of birding seasons can be written for any spot. The dates and the characters will be different for even parks as close to Sleeping Bear as Indiana Dunes or Cuyahoga Valley National Park. In far flung locations like Acadia, Death Valley, or Denali, the seasons and players will be almost unrecognizable. Given a hundred human lifetimes, you couldn't begin to experience it all, and that's the lure of birding and traveling.