Wednesday, April 16, 2014

Sea Level Rise at 3 mm per year since 1993

This current rate - 3 mm per year - is shocking. Since 1999 when I started studying Audubon's Shearwaters in The Bahamas, global sea level has risen 4.5 cm. I find nests that are right in the spray zone of the high tide, including at least one nest that I started studying in 1999. At Little Tobago, there is a shearwater nest that is below the high tide line by a couple of millimeters. They can nest in the same site for 50 years once established. When that nest originated, potentially hundreds of years ago, it was probably 10-20 cm above the high tide level. Now, it gets swamped in Spring tides and likely fails every year.

I often cynically joke that sea level rise is not a problem we will worry about for seabirds -  not because it won't kill them but because we will be so busy dealing with "natural" disasters in coastal areas that no one will think about the seabirds. But this math is pretty scary. 

Shearwaters prefer coastal nests just above the high tide line. In the image above, you can see the spray zone of Long Cay, which is uninhabitable by shearwaters, as the barren area of eroded rock without vegetation. As the sea rises, the spray zone will encroach on this prime habitat and all the nests within it could become sinks that fail every season as a spring tide or storm surge inundates the nest with saltwater and drowns the chick. 

A high percentage - maybe 10% - of their current nests will be unusable within the next 20 years. Of all the seabirds in the Caribbean, this species might be the most affected by sea level rise. Perhaps the new seabird nest boxes (see previous post) could help provide alternative sites above the tide line.

Friday, April 11, 2014

Nest Boxes for Cavity-Nesting Seabirds are Ready to Order!

Designed by David Wingate of Bermuda, these nest houses for cavity nesting seabirds represent decades of design from the world's expert on saving endangered petrels and tropicbirds.

The devices are ingeniously simple and the pieces stack inside one another. The top is vented and held on with sturdy molded tabs that lock in. They can be buried in sand, covered in rock or cemented in place, and you can install them in any location that will be safe from Dogs, Cats or other predators.

Bermuda Audubon and the Bermuda Department of Conservation Services sells the previous version and has had great success filling cliffs with White-tailed Tropicbirds. Special baffles for the entrance can limit the tunnels to smaller species including Cahows or Audubon's Shearwaters. The first 25 are available for installation in the Caribbean. Just contact me with shipping information and an explanation of when and where you will put them in. The only costs are shipping and an agreement to send pictures and reports on the success of your nest boxes.

The molds were funded by Bermuda Audubon Society, while BirdsCaribbean and the National Fish and Wildlife Federation funded the molding of the first 50 boxes. They can be used anywhere in the world. Contact me for ordering information.