Book reveals the mysterious life of seabirds

Songbirds and seabirds share flight and feathers but little else.

A chickadee lays seven to eight eggs that hatch in about 13 days. An oceangoing Manx shearwater lays one egg that hatches in 50 days. Chickadees fledge — leave the nest — in about three weeks. Albatrosses fledge in 10 months.

Chickadees are fortunate to see their second or third birthday. Albatrosses not only live into their 60s, but can lay eggs and raise chicks at that age.

Chickadees can find insect food seconds from their nest. An albatross will fly as many as 9,000 miles during one 20-day trip to find and deliver food to its incubating mate.

Seabirds are members of a family of near 350 species that live on, over and adjacent to oceans.

Until recently, seabirds were noteworthy for the things we didn't know about them: migration patterns, nesting locations, nesting biology, or even how these birds made a living at sea.

Answers came only when modern electronics made possible instruments small enough to be carried by birds — harnessed to their backs, tied to their legs, carried in their mouths or stomachs. The smallest devices weigh one gram, .03 ounces. Some are solar-powered.

Seabirds include penguins, albatrosses, fulmars, petrels, shearwaters, gannets, frigatebirds, tropicbirds and large families of gulls and terns. The albatross family has the largest seabird, one with a 10-foot wingspread. The least storm-petrel weighs less than a sparrow.

Most seabirds nest in isolated places, on predator-free islands or inaccessible shoreline cliffs. They often travel great distances for food because suitable nesting sites and productive feeding locations can be vastly separated.

(Warming seawater is troublesome in this regard. Feeder fish are seeking more suitable water temperatures, leaving behind starving birds following genetic maps.)

Songbirds, with their short lives, must replenish the species quickly. Large broods do this.

Some seabird species live for decades. Sexual maturity can take six years. These birds can afford to reproduce at a slower rate, in some cases a single annual egg.

Brooke's book explains how behavior data are captured. The devices that birds wear record satellite signals, tracking migration. Geolocators carried by the birds record sunrise and sunset, pinpointing latitude and longitude.

Instruments attached to bird legs note depth and duration of dives. Other devices sense whether feet are wet or dry. (Wet feet mean the bird is on the water.)

Temperature sensors in a bird's stomach note dinnertime. (Fresh food is cold.) Accelerometers record flight and diving speeds.

Technology has conquered our ignorance about birds that disappear over the horizon or underwater. Seabird lives remain mostly unseen but are no longer unknown.

Brooke's book will be published by Princeton University Press. It has 272 pages, is illustrated, and the price is $29.95.

One more thing: There is no such thing as a seagull. All gulls have proper names, none of which is sea. A gull is a gull is a gull.

Read Jim Williams' birding blog at startribune.com/wingnut.