Saturday, February 5, 2011

A comprehensive monitoring plan for seabirds in the Caribbean

You might say to yourself "What would a planned, coordinated monitoring program for Caribbean Seabirds cost and how would you structure it?" That is the topic of today's post. The goal of an effective monitoring plan is that it can detect a certain level of change (e.g. 25%) within the population. Right now, all we can do is say where the birds are breeding, which is a good improvement over the status prior to the earliest regional review of the entire seabird population (van Halewyn and Norton, 1984). To get to that next level, we need better counts and censuses of the populations.

We know the populations have crashed over the last century based on firsthand accounts of people who lived in the Caribbean region. Islands that were covered in seabirds every spring sit vacant or have small populations now. Are the declines continuing? Our data for most species are not good enough to say. This is important. If they are continuing to decline, we should be undertaking all drastic measures to keep them off the endangered species list. If the decline has stopped, we should still watch them but drastic measures would not be necessary.

With terns, the birds move islands between years. Roseate Terns rarely nest on the same island twice. We need to estimate the populations within wide areas every few years. There is not likely to be a big source of funding for this action, so we need to divide up the work among local volunteers who can do it with little trouble. We need to create an efficient system to gather up the data and collate it into the database that we already have. Perhaps we could simply use the eBird system that has been created. I will work on it and have a report at the meeting in Abaco in July.

I realized I left off two really good sets of data from the Bahamas. One was a sequence of surveys in the 1990's by Bailey Smith and Lorraine Minns, two naturalists who live near Great Exuma and decided with encouragement from other Bahamian naturalists to survey the seabird breeding sites. They recorded data for several years. Their data set is among the most comprehensive for any island group. A second series of surveys were those by Jim Kushlan off his own private boat. He surveyed colonies in the Berry Islands, off Abaco, and around Bimini. His contributions were very important as well. The point of these is that naturalists around the region can make important contributions, but without coordination and comprehensive planning, they are just opportunistic surveys. We cannot get a legitimate estimates of these populations without covering all of the islands regularly.

We now have the database, the knowledge of where most remaining colonies are, and a network of naturalists and biologists who are dedicated to seabirds and could reasonably monitor a subset of colonies at regular intervals. At this point, we need someone to coordinate the effort, a group of dedicated and scientifically literate volunteers who can make legitimate surveys, and the will to conduct the surveys. We may also need some funding, but it will not be exorbitant.

What we need are naturalists near each colony who will agree to regularly count the seabirds. It doesn't have to be done every year, but that wouldn't hurt. Every 5 years would be sufficient. They would need to have some Sherman-style live-capture rat traps, the ability to recognize the birds, and access to a boat. Some flagging and tape measures would be handy. We could cover most islands in the Lesser and Greater Antilles this way. There may be some very remote cays such as those in the remote areas of the Bahamas (The Plana Cays, Cay Sal Bank, Cay Lobos, The Ragged Islands, and Mira-por-vos) that would need some outside help. There are about 800 nesting islands in the entire region. We just need to divide the work and create a portal through which people can enter their data. This is a very attainable goal.

I will put together a workshop for the meeting of SCSCB in Grand Bahama this year. I'll have that portal and people can sign up for their islands.