Coconut palms fringe the white sandy beach. The Pacific Ocean is almost the same deep blue as the sky overhead. Only a few hundred feet inland from this postcard-perfect tropical beach scene the tidal mud is knee-deep and smells like rotten eggs. If the mud wasn’t enough of a challenge, a dense labyrinth of mangrove stilt roots makes it near impossible to walk. Many thousands of people visit the Nicoya Peninsula in Costa Rica each year to enjoy the former scene. RTPI Affiliate Sean Graesser and fellow researcher Tyler Christensen make the trip down each winter to spend several weeks in the latter.
Curu habitat
Curu mangrove habitat
Twan in the mangroves
Sean and Tyler jointly founded the Nicoya Peninsula Avian Research project in 2010 to learn more about Neotropical migrants on their wintering grounds and to study the biology of resident local birds that inhabit this important coastal ecosystem. Both Sean and Tyler have been working with birds in their native New Jersey since a young age. Through their involvement with local bird banding projects and long-term participation in ongoing avian research they eventually attained their federal master bander licenses and just kept going. The Nicoya Peninsula Avian Research project collaborates with the Institute for Bird Populations (www.birdpop.org) and each winter carries out a MoSI banding protocol in two sites in the southern Nicoya Peninsula: Curu Wildlife Refuge and Cabo Blanco Absolute Natural Reserve. In addition, Sean and Tyler study hummingbirds at a third site on the Nicoya Peninsula, a private preserve called Finca Pura Vida.
The crew hard at work!
Sean checking the nets
Removing a netted bird
Looking at a new capture
Examining the details
MoSI, which stands for Monitoreo de Sobreviviencia Invernal (Monitoring of Winter Survivorship) is the Central American winter equivalent of MAPS (Monitoring Avian Productivity and Survivorship) another monitoring protocol that is typically used on migratory birds’ breeding grounds in North America. Both types of study involve catching birds in mist nets in the same location over a period of several weeks. Detailed data is taken on each bird caught and before their release a uniquely-numbered federal USGS band is applied. Once banded, individual birds can be recognized and tracked over a prolonged period of time. Local birds in a particular area are likely to be recaptured repeatedly during a breeding season (in the case of MAPS) or during their wintering period (with MoSI). Such studies provide valuable information on population size and demographics (age distribution, sex ratio, etc.) in an area. In addition, recapturing banded birds in different years has given us a fascinating look into the site fidelity of breeding birds as well as in the choice of habitat that our migrants overwinter in. Banding studies have confirmed that people are often correct in assuming that ‘their’ Baltimore Oriole or Ruby-throated Hummingbird returns to their backyard each year because many birds do migrate back to the same area to breed each year.
Green-breasted Mango (Anthracothorax prevostii)
Cinnamon Hummingbird (Amazilia rutila)
Initiatives such as the Nicoya Peninsula Avian Research project and other bird banding projects in Costa Rica and Panama, supported by RTPI, reveal that these regular summer visitors are equally consistent in their choice of winter destination. In fact, in another RTPI supported long-running tropical research project in northeastern Costa Rica we have caught, banded, recaptured and recaptured again a Chestnut-sided Warbler over a span of five years. We encountered it each time on almost exactly the same date and in nearly the same tree! Clearly this bird flies north to breed somewhere in the US each year, only to return to exactly the same spot in the Costa Rican rainforest every winter! Sean and Tyler are finding similarly amazing patterns in the migrants they band at their Nicoya Peninsula study sites. Beyond the dazzling variety of local birds that inhabits the mangrove and coastal dry forest habitat there, many familiar faces and calls can be detected with ease – Summer Tanagers, Northern Waterthrushes, Tennessee Warblers, Yellow Warblers, Prothonotary Warblers, Philadelphia Vireos and many more migrants call this place home in the winter. This past December, one of the Northern Waterthrushes we captured turned out to be a bird banded by Sean and Tyler three years before. Quite incredible to imagine that such a delicate creature has successfully made the long, arduous trek from Costa Rica to North America and back several times already and here it is, stocking up on tropical insects in preparation for yet another journey north this spring!
Summer Tanager (Piranga rubra)
Prothonotary Warbler (Protonotaria citrea)
Northern Waterthrush (Parkesia noveboracensis) in hand
Philadelphia Vireo (Vireo philadelphicus)
One of the most important take-home messages of these kinds of research projects is that the health and protection of often unseen, far-away habitats is just as critical to the survival of our favorite backyard birds as their protection in the US and along their lengthy migration pathways. Unfortunately, we know far less about the habits and habitats of wintering migrants than we do about their life during the breeding season. Only through the hard work and dedication of people like Sean, Tyler and their assistants are we slowly beginning to form a more complete picture of the intricate biology of these animals. Nevertheless, much more work is needed to adequately understand and ultimately protect our migratory birds for the long run.
Leaf-hopper
White-faced Capuchin Monkey (Cebus capucinus)
The lack of information on where and how these birds spend their days when they’re not in North America is particularly troublesome. Lack of funding has caused most MoSI sites in Central America to close in recent years. RTPI supports the Nicoya Peninsula Avian Research Project and another migratory bird banding project in Rara Avis in northeastern Costa Rica, as well as a MoSI station in Cocobolo Nature Preserve in eastern Panama. The latter two projects not only provide valuable new information on Neotropical migrants and local birds but also provide unique educational experiences for high school students who travel from schools in Connecticut each year with their teachers to partner with local biologists, RTPI staff and other researchers on these projects. The synergy of providing hands-on learning experiences for students as they participate in important conservation research with local and international experts is a powerful one and everyone learns from these experiences. In addition, these projects bridge cultural and biological gaps that the birds we study transcend twice each year, providing important connections that benefit anyone involved.
An experience all students should get to enjoy!
Clay-colored Robin/Thrush (Turdus grayi), a bit different than the one we’re most familiar with
Making friends with the American Pygmy Kingfisher (Chloroceryle aenea)
The Roger Tory Peterson Institute of Natural History is committed to stimulating meaningful conservation and environmental education projects like these – projects that encourage anyone to look beyond the confines of their own backyard. To most of the animals and plants we study and care about the world is simply a continuous patchwork of backyards – some more suited than others, but connected regardless. Stay tuned for more updates from our local, regional and international projects and we’ll help you make the natural connections that may not always obvious to us but that are critical to our healthy and functional environment.
A backyard of a different type
We have to monitor these “backyards”, too!
If you want to help us support and expand the important work of Sean, Tyler and a number of other enthusiastic young researchers we work with, please contact me at tleenders@rtpi.org. Also, financial contributions to underwrite our projects are always appreciated and are tax-deductible. Every little bit helps and no donation is too small. If you want, 100% of your donation can be applied to our tropical research and conservation initiatives. Simply write ‘tropical research & conservation’ in the remarks section of your check or online donation form. It’s that simple.
Twan Leenders
President & Executive Director
Photos © Twan Leenders
