South Caicos’ salt ponds attract an amazing bird community.

Story & Photos By Liam M. Carr, Ph.D., School for Field Studies, Center for Marine Resource Studies, South Caicos

The island of South Caicos provides important habitat for over 200 species of birds, some year-round residents and others only appearing briefly as they move across the region. Mourning doves and sparrows nest along rock walls and in the scrubby brush growing across the island. Cattle egrets, introduced to the region from western Africa, diligently feed on a variety of insects as they move across grassy fields. And waterbirds like the American flamingo, tricolored heron, and the endangered West Indian whistling-duck, have found South Caicos to be an incredibly welcoming site, providing food and shelter from its offshore cays to its mangrove-fringed coast to inland fresh and salt water ponds. It is these salt water ponds, constructed nearly 300 years ago, that have helped turn South Caicos into a bird paradise.

Lesser yellowlegs wading in one of South Caicos’ abandoned salt ponds.

The island’s network of salt ponds, once a major salt producer, now sit mostly derelict, unused by humans since the early 1960s. Recognized through the Boiling Hole Area of Historical Interest as important economic and cultural artifacts of the island’s rich history, South Caicos’ salt ponds have in recent years drawn dozens of species of waterbirds to feed on dense clouds of Artemia shrimp, juvenile crabs, worms, fishes, and plant life. As a result of the emergence of the salt ponds as habitat for birds, the School for Field Studies (SFS) has begun a multi-year study on the ecology of the salt ponds and the bird community it supports.

Interest in South Caicos’ salt ponds stems from the current condition of the ponds themselves, the bird community found there, and the potential for considering the ponds Important Bird Areas (IBAs). Maintained throughout the salt production period of South Caicos, relative lack of human activity on the ponds has allowed the island to slowly reclaim many of the ponds. While a dependable source of salt water can be found arriving from the Boiling Hole, every pond is slowly silting in, becoming shallower and increasingly saline. Canals and dykes once opened and closed to channel water to various ponds have long been forgotten, with some ponds now entirely closed off to the Boiling Hole’s waters, and others permanently open. Seasonal rains flood the ponds then evaporate through the dry spring and summer months, giving the impression that the ponds are still being maintained.

In truth, what at first glance looks like a cohesive, interconnected salinas system is in fact a number of microhabitats, ranging from relatively deep, cool waters near the Boiling Hole that maintain similar salinity to the ocean, to extremely shallow, hot, hypersaline ponds toward the north end of the system, near the island’s airport. These microhabitats, in turn, affect bird community dynamics and behaviors. As they continue to change away from human disturbances or efforts to maintain them, their potential capabilities as IBAs will also change, potentially impacting the birds currently found there. Will continued reclamation back to a “wilder” state improve the salt ponds as waterbird habitat, or will changing conditions diminish the rich supply of food and shelter, forcing these birds to other islands to survive?

TCI’s iconic osprey is a frequent visitor to South Caicos’ cays.

To begin answering these questions, SFS has been studying bird dynamics and behaviors at several scales within the salt ponds and other neighboring habitats, from the individual bird moving about at fine temporal and spatial scales, up to the level of the entire island. The question of scale is central to understanding the ecological goods and services provided by the salt ponds, and answering that question will help determine the uniqueness and potential of these ponds as an IBA.

During Spring 2015, SFS built on the success of previous research by quantifying changes in micro-habitat preferences between seasons, and, for the first time, conducting a water quality characterization of the ponds. The spring begins the long dry season in the Turks & Caicos Islands, and with no rainwater arriving to offset water losses from evaporation, many of the salt ponds begin to pull away from the short rock walls that separate individual ponds, revealing the deep, soft mud that has slowly amassed over the decades since the end of commercial salt production. Food, primarily small salt-tolerant invertebrates like brine shrimp and nematodes, also become concentrated as their pools shrink, becoming a veritable feast for birds. By tying in these behaviors and habitat preferences both for feeding and resting with the underlying physical water quality characteristics, SFS researchers have identified conditions that support the island’s bird community, and how birds shift over space and time.

The dramatic changes between seasons at the salt ponds directly impacts the bird community present. Fluctuations in bird biodiversity can be attributed to the underlying environmental conditions, particularly water quality and coverage. During the wet fall months, environmental pressures on birds are reduced, leading to a more even distribution of birds around South Caicos. In the dry spring months however, the concentration of food and suitable water conditions lead to birds aggregating at productive ponds. Over time, should these ponds lose productivity through continued siltation and neglect, it can be expected that birds will be forced to move on to new waters to eat, rest, and nest.

Researchers have also begun exploring how South Caicos’ bird community compares to other IBAs in the Turks & Caicos Islands. Comparing bird counts of birds seen both around South Caicos’ salt ponds and at the Turks & Caicos National Museum IBA on Grand Turk, researchers have found that South Caicos’ springtime bird community is both more diverse and abundant than at the museum IBA. Of the twenty-nine species found in both locations, South Caicos had higher abundances in only fifteen instances. Yet, looking only at the eighteen species of waterbirds, South Caicos had higher comparative abundances in thirteen instances. Looking more broadly across the region, South Caicos ranks very highly over four species of iconic bird species popular for birding and birding-related tourism. Notably, South Caicos has greater numbers than the internationally recognized Ramsar wetlands site on East Caicos, and had the greatest overall weighted rank in both spring (April) and autumn (November) counts for all sites considered.

These four studies, from a baseline assessment on water quality to micro-scale habitat shifts and growing awareness of the importance of South Caicos’ salt ponds regionally, together provide strong incentives for policy makers to contemplate their conservation through targeted management tools, including being named an IBA.

This dramatic change in habitat and bird diversity and behavior between seasons has important implications for South Caicos. Shifts, too subtle to observe from one day to the next, are noticeable at longer time scales, reflecting the dynamic nature of these pond communities, and reveal the difficulty in managing the ponds. Have nearly fifty years of indifference led to a bird-friendly salt pond ecosystem? Is South Caicos benefitting from such benign neglect of its salt ponds, or have researchers caught only a snapshot of the current conditions, but are unable to predict what lies ahead?

Bringing the focus on South Caicos and its people, the island is showing the first tentative signs of economic diversification, with the arrival of the Sail Rock development along its eastern ridgeline and the nearly open East Bay Resort and Condominium development. Known today as the fishing capital of the Turks & Caicos Islands, these two developments envision a future where South Caicos becomes internationally known for community-oriented tourism and real estate. The salt ponds might seem prime locations for large earth works projects that might increase the visibility and attraction of South Caicos for investment and tourists.

While the ongoing focus on birds might not fully slow any such discussions, thanks to these research projects there is now an understanding of the current ecological role that these salt ponds play, and how these benefits might be lost in the coming years from either rash development projects or continuing the present policy approach of neglect. A vibrant, diverse bird community may be a natural asset that supports the island’s vision for small-scale tourism centered on South Caicos’ natural beauty and cultural uniqueness.

The School for Field Studies (SFS) is a US-based academic institution that provides multidisciplinary, field-based environmental study abroad opportunities to undergraduate university students. Each SFS program (nine in total) highlights a different region of the world, with its own distinct cultural and ecological characteristics and unique environmental challenges. Faculty and students at the SFS CMRS on South Caicos work in close cooperation with local partners including the TCI’s Department of Environment and Maritime Affairs (DEMA), TCReef Inc. (www.tcreef.org), and local fishermen and processing plants to protect and enhance the management of the island’s coral reefs and other marine resources. To learn more, go to  www.fieldstudies.org/tci.