The fox sparrow, named for the red in its tail feathers. (Jim Avelis/AP)
Gardening columnist

If you like to attract birds to your yard with nesting boxes and feeders, you’re not alone. An estimated 55 million Americans are into bird-watching and many are discovering that smartphones offer a whole new relationship with their avian friends.

Some birders are content to attract and watch birds in their own gardens; more serious hobbyists will travel near and far for the chance of spotting, recording and reporting bird species.

For the plugged-in bird person, there are dozens of apps available, said Chris Wood of the Cornell Lab of Ornithology in Ithaca, N.Y. But a new generation of apps is allowing greater interactivity and customization and can help serious birders plan trips in search of desired species.

“Some of the first ones to come out basically took the same kinds of information you could get in a field guide and put it in digital form. Now there’s a movement toward much more exciting things,” Wood said. He runs the eBird project, a vast database of current and historical bird sightings by citizen scientists. Vetted for accuracy by a network of ornithologists and updated frequently, it features in a couple of apps, including BirdsEye ($19.99, iPhone), which is favored by experienced birders who travel to view birds. Many maintain a “life list” of observed birds. The longer you are a birder, the harder it is to find species you haven’t already seen. BirdsEye calls itself “the ultimate bird finder for the iPhone.”

“One of the things that makes expert birders expert is the ability to calculate the probability of a species showing up at that date and location,” said Wood, lauding eBird’s utility.

Which phone apps do you use?

BirdsEye’s developer, David Bell, said the app also has value to novices because it narrows the range of species known to be in a given locale.

For beginners and intermediate birders, the National Audubon Society’s app ($14.99, IOS, $2.99 Android) functions as a field guide, has a crowd sourcing feature, and also links to eBird. It was developed by Green Mountain Digital in Woodstock, Vt. The company has created other Audubon guides for such things as butterflies, wildflowers and trees, “but the birding app is by far the most popular,” said David Tyler, director of product development. “I think there’s a very large and very passionate birding community.”

Another popular app is the Sibley eGuide to the Birds of North America, which features 813 bird species and beginner-friendly features that identify and compare birds by such things as size and plumage. The app is $19.99, though a sample app with 30 species is available for free.

The National Geographic Birds: Field Guide to North America was relaunched in November with additional bird species, now up to 995, and a new design. The birds are depicted in a range of eye-catching illustrations that “are our calling card,” said Natalie Jones, digital products manager. The app is $9.99, but not yet available in an Android version.

The apps generally feature something the old printed guides lacked: the sound of bird song. Like everything else about birds, the recordings can get complicated: Birds have different calls, for mating and for alarm, for example. Amazingly, they also have distinct regional differences — bird dialects — that are clearly dis­cern­ible once you listen to the recordings.

In the Sibley guide, for example, an American goldfinch from New York is ebullient and sings its heart out while one in Utah sounds more staccato and subdued.

The one thing apps have not yet achieved is the ability for the user to hold the device up to a chirping bird and get a positive identification. This is tied to the fact that bird song is so variable and because ambient noise would get in the way, Wood said.

With so many bird songs at your fingertips — the Audubon guide has eight hours of recordings — it’s tempting to go into the woods to lure desired species. But that’s considered poor etiquette because it disrupts the birds, confuses other birders and may be illegal under certain hunting statutes.

“If you played the alarm call for the American robin, you can really agitate that bird,” Tyler said.

Meanwhile, the ornithologists at Cornell are working on an app called Merlin geared to adapting the eBird database for beginners, by narrowing species to locales in real time.

This may seem a relatively simple task in the age of GPS, but many birds arrive in the spring and leave in the fall, or just pass through at those times. “When you are able to provide someone with an answer to the basic question, ‘What’s that bird in my backyard?’ it opens all the floodgates, the Google searches for all the information about that species,” said Jessie Barry, the Merlin project leader. The app should be available later this year.