Late Summer Wildlife Winter at Mandahl Bay
Wildlife winters occur several times a year. These are periods of time, usually lasting three to six weeks, when wildlife seems to all but disappear from the region. We have nick-named these unique intra-seasonal times of low life presence “Wildlife Winter”.
There are a variety of natural reasons for Mandahl’s wildlife winters. Most are related to the breeding and maturation cycles of both plants and animals.
The Mandahl Bay Area of Particular Concern and Area for Preservation and Restoration has been listed by the US Department of Interior’s US Fish & Wildlife Service as a nursery habitat. Throughout most of the year wildlife arrives at Mandahl via ocean and air from as far away as the Arctic. Some of these creatures come merely to escape the cold. Others, such as fish and ocean-going reptiles, travel here because mangrove roots and coral provide excellent cover and safety for their young.
Most creatures abandon their young to fair for their own. Mandahl Bay provides excellent food resources for the very young as well as predators. However, this tiny Eco-system provides little nutrient value for the parents of the region’s young.
Adult creatures that enter the Mandahl Eco-system merely to spawn or bear young include, among many, many others: Hawksbill, Green and (suspected) Leatherback turtles; Spotted Eagle Rays; various Parrotfish and Snappers; Lobsters; Crabs; Sea Hares and more.
Birds are a more complicated issue.
Smaller resident birds retreat into the bordering trees and shrubbery to build nests and set eggs, thus reducing sightings. However, these birds have not left the area. We just do not easily see them because they are not very active while rearing offspring.
Sea birds, shore birds and wading birds have learned, for the most part, not to build nests on St. Thomas. The island has been invaded by rats and mice that were carelessly imported to the island from Europe on colonizing ships. Because the only mammals native to St. Thomas are bats, our sea side birds never learned how to defend themselves against rodents.
The mongoose is also a severe threat to bird eggs. The mongoose was brought to St. Thomas in 1900 by the Danish. The intent was to have the mongoose kill off the imported rats and mice. However, no one informed the mongoose that it was to leave all other life alone.
As a result of these threats, many of Mandahl’s resident birds will leave to nest on the smaller outlying islands that are not inhabited by humans or rodents. As time passes, however, boaters who have been ignoring the stand-off law for these islands have allowed rodents to begin spreading there as well.
We continue to study to causes and triggers for wildlife winter so that this important cycle can continue in the face of global climate change. We have noted that the regular reduction of adult life presence also allows a new generation of life to grow into adulthood.
Some wildlife winter cycles follow times when the Eco-system becomes overgrown with algae. This algae, which appears to be dependent upon the amount of fresh water run-off entering the lagoon, provides abundant nutrients for new born fish and other critters. The algae also reduces oxygen content in the water. Thus adult predators (excepting the air-breathing Tarpon) vacate the algae-covered waters lest they suffocate.
In future posts we will go over our discoveries and studies into the causes and effects of wildlife winters. We will wrap up this post with a series of images of the life we did find present last week at Mandahl.
Please enjoy the images and, if you wish to use them for your own purposes, we have attached a royalty-free stock image license giving you all the permissions you’ll need.
Thank you for being a part of something green! 🙂
~ Karl Callwood
