No one ever said birding is easy. With 10,000 birds in the world, one inevitably encounters groups of birds that are difficult to distinguish. Hummingbirds in the New World tropics, sandpipers and sparrows are great examples. It’s easy to identify a bird as a hummingbird but which of the 340 species are you seeing?

Gulls are another group of challenging birds. Any school kid can identify a seagull but identifying the species can be perplexing.  Which of the 16 gull species in Maine are we looking at?

The difficulty of gull identification stems in part from the similarity of the different gull species. Although body mass differs among species, every gull has roughly the same silhouette.

In addition, gulls pass through a bewildering series of plumages. Gulls molt all of their body feathers every fall, transforming their appearance dramatically. In the spring, gulls have a partial molt, again altering their appearance. To confound matters further, the timing of the molts differs among individuals so birds that are the same age may look strikingly different.

Finally, gulls may take up to four years to acquire their adult plumage, called the definitive plumage in ornithology-speak. Smaller gulls like Bonaparte’s Gull require only two years to get to their definitive plumage while our larger gulls like Herring Gull and Great Black-backed Gull take four years to reach adulthood.  That’s a lot of plumages to keep track of.

To be sure, there are some birders who delight in the challenges of gull identification. Poring through flocks of hundreds of gulls to find an uncommon gull like a Lesser Black-backed Gull, Black-headed Gull, Little Gull or Sabine’s Gull is a joy to gull enthusiasts.

That level of skill is tough to come by. However, a recent book from Princeton University Press may be a gateway to allow you to acquire those skills. The book is called Gulls Simplified by Pete Dunne and Kevin Karlson. Gulls Simplified: A Comparative Approach to Identification by [Dunne, Pete, Karlson, Kevin]Yes, I am aware that the phrase gulls simplified is a contradiction in terms but the phrase fits this book.

Who knows? Maybe your improved gull identification skills will allow you to be the person who finds a Slaty-billed Gull among the hundreds of gulls at the Hatch Hill Dump in Augusta or some other gull haven!

Dunne and Karlson are both highly skilled birders and popular bird tour leaders. However, neither one has a particular passion for gulls. The authors argue their level of interest is perfect for a book that aims to fill a need for a gull identification guide that is welcoming to any birder.

The distinctive feature of this guide is that identifications are based more on general shape, size, behavior, general color patterns, habitat and comparisons to other known birds in the area. The guide downplays the feather-centered approach that gull nerds use to identify the age and species of a particular gull.

The authors rightly claim that most birders don’t really care whether the Herring Gull they are looking at is one, two or three years old. It is more important to know that it is a Herring Gull. Dunne notes that is easier for him to identify a Lesser Black-billed Gull at 200 feet than at 20 feet because he uses general impressions rather than plumage details.

Dunn and Karlson are pioneers in promoting bird identification by impression, having produced identification guides for hawks and shorebirds that use this technique effectively. The approach works for gulls, too.

The book is packed with excellent color photographs, mostly taken by Karlson. Detailed legends for each photograph describe important characteristics useful in identification. I counted 46 photos for the Herring Gull. There are several photo quizzes, as well, to test your enhanced identification skills.

The guide covers the 20 regularly occurring gull species in North America as well as five rare gulls. A section with photos on hybrids is illuminating.

Gulls Simplified” is a great addition to the wealth of bird guides we have.