Bird-Watching: Making the Most of Migration
A top North American birder shares tips for finding birds during their biannual migrations
DURING THE SUMMER AND WINTER, the numbers and varieties of birds tend to change little from day to day. Spring and autumn are different. In these seasons of transition, many birds are engaged in great geographic relocations, moving to and from breeding and wintering territories. Exciting times for bird-watchers, each day dawns with new possibilities. Here are a few lessons I’ve learned that should boost your bird-finding ability during the animals’ migrations.
• Forget Your Notion of Seasons: Did you know that across much of North America birds are migrating every month of the year? Spring migration, for example, begins in January with the arrival of the first purple martins in Florida and ends six months later with the last, nonbreeding Swainson’s and broad-winged hawks straggling north in July. What most people think of as “spring and fall migration” is actually just rush hour. In some times and places, northbound and southbound birds are passing each other in the sky.
• Study the Weather: Weather does not determine if there are birds, but it does determine which species you’ll find and where you’ll find them. Spring migrants are propelled north, for instance, by the southerly winds associated with warm fronts. In fall, cold fronts spur migration and give southbound migrants an energy-saving tailwind.
Cold, clear mornings encourage birds to forage on the sunny side of woodland edges. Windy days prompt waterfowl to gather on the protected, calmer lee side of lakes. Coastal storms and hurricanes ferry seabirds landward, while prolonged drought forces waterfowl and wading birds to wander hundreds of miles in search of good aquatic habitat.
• Follow Leading Lines: Bird migration is conducted along broad fronts, but topographic features direct and concentrate the flow of birds. Coastlines, mountain ridges, greenbelts and even large urban areas cause birds to alter their courses and come together.
• Think Globally, Bird Locally: The world hosts a handful of great migratory junctions where migrating birds are super concentrated. These include Cape May, New Jersey, and Eilat, Israel. But no matter where you live, you’ll find smaller migrant traps: verdant, sheltering pockets where birds congregate. Examples include city parks, wooded or weedy peninsulas projecting into large lakes, trees planted as windbreaks around crops and even highway rest areas in deserts or grasslands. And unlike most world-class birding destinations, you can visit your local migrant traps every day.
• Look Up: Every morning and every evening, birds are on the move, heading from roosting to foraging areas. Even in the heart of major cities, avian commuters are crisscrossing the sky. No matter what the season and location, you’ll find birds the first two hours before or after dawn and dusk.
Pete Dunne is director of the New Jersey Audubon Society’s Cape May Bird Observatory and author of many books. This article is adapted from The Art of Bird Finding, published by Stackpole Books in 2011.