Oceanic islands are fascinating to anyone with an interest in biology. Thrust up from the deep ocean floor, oceanic islands are blank canvases. Colonization of plants and animals from continental areas occurs by rafting or by being carried on the wind.

Some of these colonists establish a stronghold on the new island, enriching the diversity. Over time, these colonists often diverge from their mainland relatives, producing new species. Thus, endemic species are born, found nowhere else.

Oceanic islands often occur in groups so adjacent islands serve as sources of colonists as well. A group of oceanic islands may have shared endemic species as well as species endemic to a single island.

The Caribbean islands offer the opportunity to see a diversity endemic species. For birds, Cuba has 30 endemic species, Jamaica has 30, Puerto Rico has 18 and the winner in the endemic species contest is Hispaniola (the island shared by Haiti and the Dominican Republic) with 32.

Other smaller islands have their own endemic species. In addition, some species are restricted to the Caribbean but are found on multiple islands. Altogether, the Caribbean offers over 170 bird species that can be seen nowhere else.

In January, my wife, Bets, and I, along with our friends, Pat and Dave Lincoln, participated in a guided tour of the Dominican Republic with the goal of finding all 31 endemic bird species (one Hispaniolan endemic is found only in Haiti).

As a hedge against a winter storm in Maine, Bets and I booked a flight a day early to make sure we would arrive in the Dominican Republic when the tour started. We used that extra day to explore the colonial area of Santo Domingo. We had no trouble finding our first endemic, the palmchat. This streaked bird, about the size of a blue jay, is common everywhere. It is the Dominican national bird. This species is so different from other birds that it is placed in its own family, the Dulidae. DNA comparisons tell us that waxwings are its closest relatives.

We found Hispaniolan parakeets as well. Oddly, this species seems to be most common in urban areas. Other species seen included Antillean palm swifts, gray kingbirds, magnificent frigatebirds and bananaquits.

Our tour began the following day with a trip to the National Botanical Garden in Santo Domingo. Antillean grackles greeted us at the gate. The cement trails through the extensive garden made for easy walking.

We saw lots of familiar birds, particularly warblers. Black-and-white warblers, Cape May warblers, American redstarts, northern parulas and prairie warblers were common. Stolid flycatchers flitted around as well. A red-legged thrush was spectacular in the sunlight.

With considerable effort, we got good looks at black-whiskered vireos. We got great views of a Hispaniolan lizard cuckoo and Hispaniolan woodpeckers, our third and fourth island endemics of the trip.

A few West Indian whistling ducks, including eight polka-dotted ducklings, showed nicely.

We saw a few tiny vervain hummingbirds, the second smallest bird in the world, barely larger than the Cuban bumblebee hummingbird.

On the way out, we found a black-capped palm-tanager, another endemic I was keen to see. This species, along with three other Hispaniolan species, is placed in its own family, the Phaenicophilidae.

With five endemics under our belt, we headed to the southwestern part of the country. Our home for the next two nights was Villa Barrancoli, a field station in Puerto Escondido. Arriving late in the day, we got a nice look at white-necked crows for another endemic species under our belts. A brief walk at dusk yielded common callinules, green herons and a Baltimore oriole.

After a nice dinner, we all hit the sack. We departed at 4 a.m. in three four-wheel drive vehicles the next day for one of the most memorable birding days of my life.

Herb Wilson teaches ornithology and other biology courses at Colby College. He welcomes reader comments and questions at

whwilson@colby.edu