White-crowned Pigeon Survival Game

An adult White-crowned Pigeon sits atop a bare tree.
Copyright 2018 Flickr user cuatrok77.

Life as a White-crowned Pigeon is full of challenges. Migrating, parenting, surviving hunting season, and finding consistent food are all on a pigeon’s yearly to-do list. Trelawny, a female tagged in Jamaica over 4.5 years ago, and South Glades, a male tagged in Florida in 2015, are two White-crowned Pigeons who are persisting despite these obstacles. In fact, these two birds are the longest-tracked White-crowned Pigeons to date!

Trelawny and South Glades are being tracked with lightweight, solar-powered satellite transmitters weighing 5 grams.

White-crowned Pigeons can only be found throughout the Caribbean, in southernmost Florida, and in parts of coastal Central America. Most of the population is migratory; some pigeons travel between countries while others move to different habitats within the same island. Trelawny, an example of the latter, spends her whole year in Jamaica and moves 7-14 miles between the coast in the non-nesting season and the mountains in the nesting season. South Glades, in contrast, nests in south Florida and migrates to Cuba in the winter.

A White-crowned Pigeon amidst ripe Poisonwood fruits.
Copyright Florida Fish and Wildlife.

The timing of these migratory movements coincides with the ripening of fruit-bearing trees like Poisonwood (Metopium toxiferum), Fig (Ficus sp.), and Blolly (Guapira sp.). In Florida, Poisonwood is the most important food for nesting White-crowned Pigeons. The nutrient-rich fruits are easily digestible and give pigeons like South Glades enough energy to make daily, repeated trips between inland foraging spots and the predator-free, offshore mangrove island where he raises his young. And where the pigeons defecate, new fruit-bearing trees sprout and create more habitat for the birds.

When the flush of ripe Poisonwood fruits ceases, South Glades departs to Cuba. Every trip over water -  with no place to rest - puts a bird in danger. Last month, on 1 September, he completed his fourth migration to Matanzas, Cuba. He left just before the skies filled with hungry hawks and falcons as they too made their winter migrations. This was at least his seventh trip across the Straits of Florida!

On 1 September 2018, South Glades migrated south to Matanzas, Cuba. 

Migrating long distances over water is risky, but staying on one island has its own threats. White-crowned Pigeons are not hunted in Florida, but they are in Jamaica and many other parts of the Caribbean. Jamaica’s dove hunting season lasts about a month from August to September. There is a bag limit of 15 White-crowned Pigeons per season, but illegal take is common and hard to regulate. Thankfully, Trelawny appears to have figured out how to evade the hunters. We are excited to see how long we can track her movements in Jamaica.

ARCI has been tracking the movements of White-crowned Pigeon since 2002. We have learned a great deal about the range-wide movements the birds make between The Bahamas, Cayman Islands, Jamaica, Cuba, and south Florida. The more pigeons we track, the more we will continue to learn about range-wide breeding, foraging, and wintering locations; migration timing; and longevity and survival. 

Click here to support Trelawny and South Glades. Your generous donation keeps the stream of data flowing from their transmitters to all of us.

Our first account of ARCI’s exciting new research on Mangrove Cuckoos in Florida

Mangrove Cuckoo Cross Dike with visible antenna
from a 2-gram satellite transmitter.
Photo by Aaron Kirk

ARCI’s biologists have found that many conservation-related research questions can be answered best by employing some type of tracking technology. Our study subjects, which include birds of various families, sizes, and habitat associations, have benefited from this approach. These include Swallow-tailed Kites, Short-tailed Hawks, Reddish Egrets, White-crowned Pigeons, Crested Caracaras, Great White Herons, Peregrine Falcons, Snail Kites, Southeastern American Kestrels, and Magnificent Frigatebirds. Although telemetry’s use is limited somewhat by the essential permitting requirement that the equipment not exceed 3% of a tagged bird’s body weight, there has been no shortage of imperiled birds large enough to carry the best-available tracking devices. Of course, this still leaves data needs unaddressed for the many species of smaller birds requiring conservation action. 

Fortunately, the ongoing development of smaller and more sophisticated telemetry devices has allowed us to keep gradually unraveling the behavioral secrets of smaller and smaller birds. One such species, the Mangrove Cuckoo, was of great interest to ARCI’s researchers in 2015 when Microwave Telemetry Inc. (MTI), our long-standing source for satellite-telemetry devices, asked us to test their prototype 2-gram solar-powered transmitter – the smallest satellite-tracking device ever developed. No one has ever determined the wintering destinations of Florida’s breeding Mangrove Cuckoos, or whether they migrate at all. This is vitally important information for this species, which is thought to be declining across its small global range. To make such a project possible, MTI donated four of their 2-gram transmitters to ARCI (they now sell for $4,500 each).

At the time, ARCI already had been using MTI’s larger satellite transmitters with great success to study the movements and ecology of Reddish Egrets in Florida, including a population on the J. N. “Ding” Darling National Wildlife Refuge (NWR), Sanibel Island, Florida. This declining species is one of the relatively few birds considered seriously threatened by the Florida Fish and Wildlife Conservation Commission. The Ding Darling NWR has been a very receptive and supportive site for our egret studies, and they were particularly interested in seeing ARCI conduct Mangrove Cuckoo research to expand on results of prior cuckoo research and to tackle questions about seasonal movements and nesting ecology using this amazing tracking tool.

From August 2015 to February 2018, we safely deployed MTI’s four donated 2-gram satellite transmitters on Mangrove Cuckoos inhabiting Ding Darling NWR. Although transmitter lifespans have been relatively short (likely due to the vulnerability of the tiny radios and their fragile antennas), we received over 12 cumulative months of reliable data from the first three birds. Virtually all the satellite fixes for these three birds were on Sanibel Island, suggesting that long-distance migration might not be occurring.

Mangrove Cuckoo Indigo East just prior to release,
showing the 2-gram satellite transmitter.

The only exception was a movement in early April 2016, at the start of the nesting season, by Indigo East, a bird that had over-wintered on the Refuge after we tagged it the previous November (tracked birds are named after their capture location). In this case, Indigo East quickly traveled six miles north, across a wide channel, and settled in a small area within the mangrove forest along the western shore of Pine Island. Here it remained until we stopped receiving data two months later. Had it moved there to nest?

This intriguing behavior, although inconclusive, suggested that Mangrove Cuckoos wintering on Ding Darling NWR may indeed move elsewhere when it comes time to nest, but the distances may be very short. Was this a rare exception, or is such behavior the rule? Do birds that breed on the Refuge move southward off of Sanibel Island for the winter? How many Mangrove Cuckoos nest on the Refuge, and how productive are they? As is usually the case, new information led to still more questions.

We recently received our most important results to date. Cross Dike, the fourth and final Mangrove Cuckoo we tagged with a donated transmitter (last February, as a wintering bird) made a sudden move northeastward on a track similar to that taken by Indigo East two years before (see Figure 1). Furthermore, both birds moved during the same week in April. The only difference was that Cross Dike traveled an additional six miles across a second channel before settling in the broad mangrove forest on the western shore of Cape Coral - a total of 12 miles from its wintering area on Sanibel.

 

Figure 1. Early breeding-season movements of two satellite-tracked Mangrove Cuckoos from established winter ranges on Sanibel Island, Florida. Indigo East (white) moved to Pine Island on 6 April 2016 and remained at least until early June, when data transmission ceased. Cross Dike (red) moved to Cape Coral on 12 April 2018, where the bird remains as of this update.

Obviously, we are working with a small sample of tagged Mangrove Cuckoos. However, we now have highly consistent movement data, on fine time and spatial scales, from these two study birds whose tracking periods have bridged the wintering and breeding seasons. This is very exciting!

Given our very exciting recent tracking results for Mangrove Cuckoos from Ding Darling NWR, we are hoping to expand ARCI’s tracking studies of this species both in scope (to include more tracking, plus nest-finding and monitoring) and geography (to other Florida populations, and eventually to Cuba as part of our long-term collaborations with University of Havana faculty and graduate students). At the moment, we are awaiting a decision from Ding Darling NWR’s staff on a proposal they requested for expanding our current Mangrove Cuckoo research on the Refuge.

ARCI is grateful to Microwave Telemetry, Inc., and particularly to Dr. Paul Howey, for their very generous contribution of the essential transmitters for the first phase of the Mangrove Cuckoo study. We also thank Refuge Manager Paul Tritaik for permission and logistic support for conducting this work on the

Ding Darling NWR.  The Refuge staff is dedicated to carefully managing this public conservation area’s diverse and sensitive resources with the best available information. The fundraising and outreach efforts of the Ding Darling Wildlife Society (the Refuge’s illustrious “Friends” organization), and the support of Sanibel donors Judy Samelson and Bill Schawbel, have been instrumental in the project’s success. We also are grateful to ARCI’s universe of followers and supporters for their willingness to share in and support our common mission.

We look forward to updating all of you on our progress, and to sharing what we learn as this exciting project unfolds.

Happy Tracking Anniversary to a Persistent Jamaican Pigeon!

Ricardo Miller prepares to release Trelawny after a successful tagging.

WOW!  We’ve been tracking Trelawny, an adult, female, White-crowned Pigeon (Patagioenas leucocephala) for 4 years using the smallest satellite transmitter made at the time of its capture, a 5-gram solar unit made by Microwave Telemetry Inc.

A big “Thank You” to ARCI’s collaborators, the Jamaica National Environment and Planning Agency (NEPA), especially Ricardo Miller; and for the assistance of Susan Koenig of the Windsor Research Centre.

All of Trelawny’s days since tagging have been spent within Jamaica’s Trelawny Parrish, on the north central part of the island. She has two focal areas that are about 5 miles apart. Most of the year, she resides in Cockpit Country, inland near the town of Duanvale, where there are plenty of native fruit-bearing trees. Occasionally she comes down to the coastal lowlands to make use of different food sources and to roost near Falmouth.

This bird has persisted through four regulated hunting seasons within Jamaica. The hunting season lasts 6 weeks in August and September and is approved each year by the Prime Minister under the recommendations of the Natural Resources Conservation Authority. All hunters need to obtain a $160 (US) license from the National Environment and Planning Agency (NEPA).

Today we want to recognize her tenacity and all the highly informative data we received from her. Trelawny has been tracked longer than any other White-crowned Pigeon. The next longest was a bird we tracked in Florida for 2.1 years.

ARCI has now satellite tracked 16 White-crowned Pigeons throughout much of their range in the Cayman Islands, Jamaica, Bahamas, Puerto Rico and Florida for a multi-partner research project entitled “Seasonal movements of White-crowned Pigeons tracked by satellite telemetry: Identifying trans-national threats, management needs, and conservation opportunities."

Source: The Cornell Lab of Ornithology, All About Birds

The White-crowned Pigeon is widely distributed throughout the Caribbean, but the species is threatened by habitat loss, poaching, and, in some countries, harvest regulations that are not based on scientific data. With satellite telemetry, we are informing wildlife managers of seasonal changes in distribution, identifying manageable threats, and documenting the need for concerted conservation planning across national boundaries. 

You can follow the movements of the tagged White-crowned Pigeons through a link on our website: http://arcinst.org/arci-tracking-studies.