With a big telephoto lens, you can photograph easily spooked birds, such as this barn swallow perching atop some concertina wire near the San Francisco Bay in Palo Alto, California.

Thousands of birders descend upon a half-mile boardwalk to see warblers each May in northern Ohio’s Magee Marsh Wildlife Area. The warblers migrate north but stop at Magee Marsh to rest up before crossing Lake Erie. Even with apps and digital cameras making birding easier, binoculars remain a nearly universal birding tool.

Connecticut birder Tim Thompson keeps track of birds in a notebook, but then logs the species on the eBird service so other birders can benefit from his sightings.

Planning a trip? The eBird service tells you which weeks to travel if you want to see birds in a particular region. It’s also useful for figuring out what’s near your own home if you’re getting started.

Bird photographers can’t get enough telephoto reach, but the best lenses are extremely expensive and heavy. Four photographers here are using Canon’s smaller 100-400mm zoom lens.

I photographed this common murre with a huge 600mm lens that magnifies subjects but makes it harder to frame the shot from the heaving deck of a ship. This murre just caught a fish in the Pacific Ocean west of San Francisco.

Keith Barnes, a South African living in Taiwan, carries a massive 500mm Canon supertelephoto lens and Leica Ultravid binoculars. The birding expert works for Tropical Birding, which runs 120 bird tours a year for avian enthusiasts.

It’s never too young to start birding, and binoculars remain nearly universally used among birders.

Lots of US birders are retireees, but there are plenty of younger ones, too. This teenager at the Biggest Week in American Birding event had better camera equipment than most adults and knew his bird IDs.

Thousands of birders submitted bird sighting data to eBird during its Global Big Day in May.

A ruddy turnstone looks for tasty tidbits among the rocks on the shore of Lake Erie in northern Ohio. The bird got its name from the way it flips stones over to find food. CNET’s Stephen Shankland photographed this with a Canon 7D Mark II SLR, 100-400mm lens all the way out to 400mm, and a 1.4x teleconverter — a relatively portable and affordable camera setup.

The warbler migration through northern Ohio often takes place before trees have little foliage, but not in 2017. These birders walk Magee Marsh’s well-known boardwalk trail in northern Ohio.

CNET’s Stephen Shankland photographs birds in Point Reyes National Seashore, California, using a massive telephoto lens to magnify distant subjects.

Several license plates declared people’s birdwatching passion at the Biggest Week event.

A great blue heron snatches breakfast out of San Francisco Bay estuary in Palo Alto, California. Big sensors on full-frame cameras are better at freezing the action, especially during dim mear.

CNET’s Stephen Shankland photographs birds on Lake Merritt in Oakland. The 600mm lens barely fit in his photo backpack even after stripping out interior compartments.

Many birders use spotting scopes to magnify distant birds. Expensive models from companies like Swarovski, Zeiss and Leica cost thousands of dollars. Adapters let you attach phones or cameras to take photos.

Magee Marsh and the adjacent Ottawa National Wildlife Refuge are unspoiled, but they’re located in an industrial part of Ohio. Four miles east, the Davis-Besse Nuclear Power Station cooling tower releases steam into the sky.

The Magee Marsh boardwalk in northern Ohio offers plenty of spots to keep an eye out for small songbirds called warblers.

Noah Strycker, a professional “bird nerd” from Oregon, saw a record 6,042 birds in 365 days of birding around the world in 2015. He chronicled the trip in a book, “Birding Without Borders.” Here, he’s standing along the Magee Marsh boardwalk, holding a Canon camera and 400mm telephoto lens along with his usual binoculars. He’s good enough to identify many birds just by their calls and songs, though.

Steve and Alli LaChance check out the warblers that can be found migrating through Magee Marsh in northern Ohio.

Cars make a good hide, a secluded spot to photograph birds without spooking them. CNET’s Stephen Shankland and a 600mm Canon lens here takes up most of the front seat in Point Reyes National Seashore, California.

You don’t need to be miles away from civilization to see birds. This song sparrow was singing vigorously in the middle of San Francisco.

The preferred birding gear for CNET’s Stephen Shankland: a Canon 5D Mark IV SLR, 600mm supertelephoto lens, 1.4x teleconverter, Wimberley tripod head and Gitzo carbon-fiber tripod.

Small shorebirds are collectively called “peep” because they often are hard to tell apart. I used the Merlin Bird ID app to figure out that this is a western sandpiper poking through the shallow water for food in the San Francisco Bay.

A black phoebe, a type of flycatcher, sings in the morning in Palo Alto, California.

Magee Marsh is a birding hotspot, and thousands of birders descend upon the Ohio wildlife area as warblers migrate through on their way to Canada.

Two women look up details on the prothonotary warbler while strolling near Magee Marsh in northern Ohio.

A black-crowned night heron attacks prey in the shallows of San Francisco Bay at dawn in Palo Alto.

The Sibley eGuide to the Birds of North America lets you track birds you’ve seen — including plenty of warblers in northern Ohio’s spring migration season.

A common murre swims on the Pacific Ocean near the Farallon Islands 32 miles west of San Francisco.

A black-throated blue warbler looks over its shoulder.

Alli LaChance looks at an app called Chirp that quizzes you on bird songs. Birds often can be heard better than seen.