Gulf Coast Whimbrels, Spring 2021

Whimbrel (Numenius phaeopus) have been identified as a conservation priority in the Atlantic Flyway, with a population that has declined by 50% between the early 1990s and the mid-2000s at key Atlantic staging areas. Manomet, along with the Center for Conservation Biology at William & Mary and many other partners are working together to gather all the information we need to apply conservation action to Whimbrel populations. In April 2021, Manomet’s Brad Winn and I headed to the Gulf coast to expand our recent work in the Atlantic flyway into the Midcontinent Flyway. Our goal for this trip? To delineate key staging areas for Whimbrel in Louisiana and Texas and build relationships with the key conservation players.

Why are we so focused on the spring staging areas for Whimbrel? In the conservation field, monitoring population size and trend is essential to understanding the cause-effect links between management actions and population response. Therefore, one of the first questions we need to ask as we build a conservation strategy is: How many Whimbrel are there, and how do we count them? This, in itself, is quite the challenge. For ¾ of the year, Whimbrel are largely inaccessible. During the breeding season, they are thinly dispersed throughout the vast Arctic and sub-Arctic tundra. During fall migration, a large percentage fly straight out over the Atlantic Ocean, without ever passing through the lower 48 states. During the winter months, they are dispersed along the coasts of the Caribbean and northern South America, a coastline which is remote and difficult to survey. Therefore, the only time to do population-level headcounts of Whimbrel is at spring staging areas, and particularly at their nocturnal roost sites. There may just be a few of these roosts in a region, pooling birds from up to 50 miles away and numbering thousands of birds.

Manomet and our partners have been identifying these sites developing survey strategies in the Atlantic Flyway for the past several years, and we have built a monitoring network for roost sites along the Atlantic coast, including focal areas such as Virginia, South Carolina, and Georgia. Our goal in 2021 is to expand this monitoring network into the Gulf coast.

Where to survey

Over the last 10 years, Manomet and our team of partners have deployed over 40 transmitters on Whimbrel at various sites in North America. This mountain of data has vastly improved our understanding of Whimbrel migratory pathways, resource use, and survival. For our trip to the Gulf coast, the information relayed from these transmitters combined with publicly available ebird data helped us hone in on key sites to explore. For example, we analyzed the daily commutes of a satellite tagged bird in Louisiana, as it traveled from a coastal roost site inland to rice and crawfish fields to feed during the day. Those feeding areas happened to coincide with the largest concentrations of Whimbrel reported in ebird over the past decade, some of which numbered over 500 individuals. This allowed us to hypothesize that the coastal roost site identified by the satellite data could be functioning as a nocturnal roost for all those birds.

To test this hypothesis, we coordinated with refuge staff to do an evening survey in Rockefeller Wildlife Refuge, the location of the potential roost site. While we knew at least one bird (the satellite-tagged bird) was roosting there, we entered the night of 4/19 not knowing if any other birds would show up. We climbed onto an excavator to gain some elevation and started scanning the horizon for Whimbrels. What started out as a trickle soon turned into a flood, and by the end of the survey, we had tallied over 3,000 Whimbrels arriving onto the refuge. A great discovery! This count alone puts south-central Louisiana on the map as one of the top spring staging areas for Whimbrel on the Atlantic and Gulf Coasts. We did subsequent surveys the following two nights and were joined by State Ornithologist for LDWF, Robert Dobbs. We were thrilled to share our methods with Robert, and he and Louisiana Audubon have now joined forces to continue the surveys.

 

crawfish farm

rice

muddy field

During the day, we covered the working lands north of Rockefeller, which mostly include vast rice and crawfish fields. In addition to the roost surveys, we are keen on increasing our understanding of how Whimbrels are using this landscape and finding the resources they need to successfully continue their migration.

 

Texas

After Louisiana, we headed to east Texas and the area surrounding Anahuac NWR. Similar to Louisiana, a combination of historical surveys, e-bird observations, and our transmitter data had clearly highlighted this area as a major concentration point for Whimbrels. We met up with Joseph Marty, the refuge biologist, and once again plotted our survey strategy. We had also received helpful intel from a team of University of Oklahoma researchers, who had been out scouting the previous week. We did four days of dawn and dusk surveys, and also spent the daytime scouting the terrain to find out what areas the birds were feeding on. Our peak count for the roost on the refuge was over 5,000 birds, making this the second-largest concentration of Whimbrels we know of on the Atlantic and Gulf coasts.

cow pasture

Whimbrel on a sod farm in Texas_BW

In Texas, we found Whimbrel using a surprising variety of habitats and feeding on a wide array of food items. This covered the spectrum from browsing on dewberries in overgrown pastureland to gorging on ghost shrimp on coastal flats with Willets and Long-billed Curlews.

Rockefeller Whimbrels 2

Rockefeller Whimbrels 3

The best way to survey for Whimbrel is at dawn and dusk when they are commuting from and to their communal roosts, which can be located in coastal impoundments, peninsulas, and islands. They fly in flocks both big and small, with roosts sometimes numbering several thousand individuals. With a total population for the Hudsonian subspecies likely under 60,000 total birds, identification and conservation of these roosts is a major priority.

 

Ahanu Aug 2019_BW

whimbrel eating ghost shrimp_BW

We met up with USFWS biologists in the area of the mouth of the Brazos River to explore the staging area for Ahanu, a Whimbrel we tagged in Massachusetts in 2018. While we didn’t spot Ahanu, we did see lots of Whimbrels. They were foraging for fiddler crabs and ghost shrimp in the tidal flats and Salicornia, and hopping onto driftwood at the mouth of the river to roost.

 

Buff-breasted Sandpiper photo

Buff-breasted Sandpipers are another priority shorebird species that relies heavily on the Midcontinent Flyway during spring migration. Concentrations of several hundred can be found in shortgrass habitats, including cattle pastures and turf farms. Manomet is one of several organizations working together to put the pieces together to ensure that we are taking the right steps to ensure their survival.

Big picture

After just 10 days in the field, we left feeling that we had accomplished a great deal. At the same time, we view this trip as just the first step in developing a conservation strategy for Whimbrels on the Gulf coast. In addition, we as an organization are also focused on the big picture, and we are intent on increasing our role as a leader in applied science and conservation work in the Midcontinent Flyway. We want to focus our work on high priority species such as Whimbrels and Buff-breasted Sandpipers, while also expanding our shorebird monitoring across the Gulf coast. We are also focused on laying the groundwork to identify and build coalitions to nominate new WHSRN sites in Louisiana and Texas.

 

with LDWF State Ornithologist Robert Dobbs

Tracking Semipalmated Sandpipers in Brazil

During November and December of 2018, a team of shorebird scientists led by New Jersey Audubon and Tulane University went on a month-long expedition to Brazil. The trip, a part of a multi-year regional effort, centered around the deployment of nano-tags on Semipalmated Sandpipers (Calidris pusilla) to help generate overwinter survival estimates for the species. These estimates will be used along with survival estimates from studies during migration and breeding periods to develop life cycle migratory network models to investigate what period during the annual cycle might be driving population declines. The target locations for this trip were two sites on either side of the mouth of the Amazon River, in the states of Amapá and Pará.

Our team included Dr. David Mizrahi of New Jersey Audubon, John Herbert of Tulane University, Bracken Brown, a Pennsylvania ornithologist and teacher, Onofre Montiero of Aquasis in Brazil, and Alan Kneidel, Staff Biologist at Manomet. We were also joined by Dr. Carlos David Santos, Professor at the Federal University of Pará.

The photos and captions below, taken and composed by Alan, are meant to share the team’s experience.

satellite photo

Located south of the mouth of the Amazon River, the Brazilian state of Pará is a tropical, biodiverse region. This satellite image gives an idea of what the coastline looks like there. While many parts of the interior have been deforested, the sinuous, mangrove-bordered coastline is comparatively remote. This region extends into the neighboring state of Maranhão and the area known as Reentrâncias Maranhenses, a WHSRN site of hemispheric importance for Nearctic shorebirds. While hosting many species, this habitat is of particular importance to populations of Black-bellied Plover (Pluvialis squatarola), Ruddy Turnstone (Arenaria interpres), Eastern Willet (Tringa semipalmata semipalmata), Whimbrel (Numenius phaeopus), Red Knot (Calidris canutus rufa), and Semipalmated Sandpiper (Calidris pusilla).

boat

Access is difficult, and the isolated communities rely on boats for transportation. The boats themselves come in a flamboyant array of colors and designs. The assistance of the locals was invaluable, both for logistics and for their insight into local shorebird behavior.

tower

We successfully deployed over 70 nano-tags on Semipalmated Sandpipers (Calidris pusilla). Nano-tag technology allows for up to 2,000 tags to be assigned to a single radio frequency while retaining the ability to identify individual animals. Transmitters are picked up through a network of widely-spaced towers that have been constructed along the coastline. The towers take a solid two days of work to erect. Here, one of the two towers we built is adopted as a favorite perch by a Black Vulture (Coragyps atratus).

Bird Processing

The team processes birds in our mobile field station on the Ilha de Maracá in the state of Amapá. At this site, our trapping efforts centered on a mangrove high-tide roost, often forcing us to work through the night.

fiddler crab

Fiddler crabs (Uca sp.) are widespread in mangroves and saltmarshes throughout the world. Wherever they are found, they serve as a principal food source for a variety of coastal waterbirds. In Brazil, Whimbrel (Numenius phaeopus) and Scarlet Ibis (Eudocimus ruber) use their long, curved bills to extract crabs from their burrows. Meanwhile, birds such as Eastern Willet (Tringa semipalmata semipalmata), Wilson’s Plover (Charadrius wilsonia) and Gull-billed Tern (Gelochelidon nilotica) have stout bills, specialized for feeding on actively foraging fiddler crabs.

wilson's plover

The Brazilian coast is home to a substantial population of Wilson’s Plovers (Charadrius wilsonia), likely augmented by wintering birds from the north. At one of our field sites, we found a flock of 50+ in the dry dune ridges. Among the Wilson’s were lesser numbers of Collared Plover (Charadrius collaris) and Semipalmated Plover (Charadrius semipalmatus).

sanderling

Many shorebirds molt their feathers while on their wintering grounds, a process that is energetically demanding. This Sanderling (Calidris alba) is replacing its greater coverts, revealing the vivid white base to the secondary feathers.

flying Whimbrel group

According to estimates, the Brazilian coast is home to up to 44% of the South American population of (Hudsonian) Whimbrel (Numenius phaeopus hudsonicus). This number includes adult birds that spend the winter months here before returning to North America to breed, as well as juvenile birds that can stay for over a full calendar year. To better understand the migration ecology of this declining subspecies, shorebird researchers in the Atlantic Flyway (Center for Conservation Biology, Georgia DNR, Manomet) have been tagging Whimbrel with satellite transmitters over the past several years. Many of these birds have spent the non-breeding season along this portion of the Brazilian coastline, including Ahanu, a Whimbrel tagged by Manomet staff on Cape Cod in the fall of 2018. Ahanu continues to winter on the outskirts of São Luis, Brazil.

upclose Whimbrel flying

Poaching is one of the greatest problems facing shorebird conservation in Brazil. In the Brazilian state of Ceará, the Whimbrel (Numenius phaeopus) is called “Pirão Gordo.” “Pirão” is a mixture of fat and flour used to make a thick gravy, and “gordo” means fat in Portuguese, referring to the Whimbrel’s size. While the hunting of shorebirds is illegal in Brazil, enforcement is a challenge.

roosting Whimbrel flock

As is the case for most birds that rely on the intertidal zone for foraging, high tide is a time for roosting. Whether a tern, skimmer, shorebird, or heron, the sand spit outside of the small village we stayed in was the place to be at high tide. Here, a flock of over 200 Whimbrel (Numenius phaeopus) rest.

SESA and SBDO

A flock of Semipalmated Sandpipers (Calidris pusilla) and Short-billed Dowitchers (Limnodromus griseus) wheel about as they settle into their high-tide roost.

Bar-tailed Godwit

Among the regular suspects in Pará, we also spotted a few (European) Bar-tailed Godwits (Limosa lapponica lapponica). Recent explorations to this stretch of coastline have begun to reveal a pattern of regular occurrence for this species in Brazil.

scarlet ibis

Without a doubt, the bird most emblematic of this region is the Scarlet Ibis (Eudocimus ruber). We regularly saw ibis feeding on the tidal mudflats and flying to and from their roosts at dusk and dawn. In Portuguese, the ibis is known as Guará, a word originating from the indigenous Tupi people.

Southern Caracara

This Southern Caracara (Caracara plancus) has just finished gorging on a washed-up carcass. The crop, bulging out through the breast feathers, is used to temporarily store food prior to digestion. Being able to store food like this is all the more important when competing with the local Turkey Vultures (Cathartes aura) and Black Vultures (Coragyps atratus).

team walking in Apeu

The team walks down the main street of Apeu, in Pará. From left to right: Bracken Brown, Onofre Montiero, John Herbert, and David Mizrahi. The trip to this village required a full day of driving on dirt roads followed by an overnight journey by boat.

 

The Last Days

The breeding bird scene on the Canning River Delta begins to wind down in earnest by the second week of July. Active shorebirds nests dwindle into the single digits, and soon only loons and a few waterfowl nests are all that remain active. Flocks of sandpipers and plovers are seen flying overhead and in the distance skeins of sea ducks can be seen following the coast westward. The Beaufort Sea ice has devolved into bergy bits and rumors of Polar Bears on the barrier islands trickle through the satellite communication waves.

Just like the shifting seasons, life in the Canning camp begins to change as well. Our nest-checking circuits through the study area shorten and the pile of completed nest cards grows. Hours spent nest-searching become hours spent entering data and contemplating the future. Fresh bread and vegetables become a distant memory, replaced by pilot bread and peanut butter. The time has come for the literal scraping of the bottom of the barrel and the redefinition of delicacy. Yes. It is time to throw stuffing mix into a bowl of ramen noodles and eat handfuls of Hall’s throat lozenges for dessert.

What are the last few days of camp really like? Here is a series of photos that help encapsulate what Patches, Alex, and I were up to.

1

Ever wonder what permafrost looks like? The bluffs along the Beaufort Sea slump in the mid-summer heat, revealing their icy core. The tundra wetlands that Arctic wildlife rely upon sit atop this frozen layer, creating habitats typical of much wetter environments.

2

One of the fixtures of mid-July at the Canning is waterfowl migration. It all starts with the exodus of males from the breeding grounds, like this flock of White-winged Scoters flying high directly over camp.

One of our final nights through camp, we spotted a medium-sized Caribou herd in the distance headed our way. Alex and I laid low in the tundra mounds and the herd continued in our direction. Turn up the volume and listen to those grunts!

3

Before anything could get packed up, we had to do a complete inventory of camp, covering everything from the number of tuna cans (60) and rolls of toilet paper (1) to the number of binder clips (75) and tent stakes (200). While doing this, we had to decide which items could stay in camp and which would need to return to Fairbanks for the winter. Then, we assigned each item staying in camp to a bear-proof metal drum that we lined with a thick plastic contractor bag and sealed up with a desiccant. Here Alex takes a break to scan for mammals while getting photobombed by just a few midnight mosquitos.

4

Spearheaded by the enthusiasm of Patches, we set out to bury two barrels to be used as refrigerators for the 2018 field crew. This is a task that can only be done during mid-summer, when the permafrost has receded enough to allow excavation. Come next spring, the barrels will be locked into the frozen soil. What does that translate to? More cheese!

5

The final task was to assemble all gear that was remaining in camp into a fortified pile to withstand the Arctic winter blitzkrieg of -50°F temperatures, hurricane force winds, and darkness. How to prepare for such an onslaught? In addition to sealing everything in metal drums, we used wooden planks to elevate everything we could and used two large weather resistant canvas tarps as protection, driving large nails through each grommet. We then used all the rope we had to tie the beast down in every direction.

6

On the morning of July 17th, I called refuge pilot Dan Shelden in Fairbanks to report a 1,000 ft. cloud ceiling and improving visibility of the Brooks Range. He reported that the weather was suitable for flying on his end. Showtime!  After the four-day scramble to pack up camp, all there was left to do was to drag everything headed back to Fairbanks down to the runway and wait for the sounds of the Cessna 185. This photo shows my personal belongings after I broke down my tent and before I descended to the riverbank landing strip. Dan arrived around 1:00 pm and made two flights to Galbraith Lake ferrying Alex and gear before heading from camp back to Fairbanks with Patches and me on the 3rd and final flight.

Our flight back to Fairbanks took us from our camp on the Arctic coastal plain back south over the Brooks Range and into the boreal forest. To be able to observe this unspoiled wilderness from this perspective is something that will stay with me forever. The rainbow wasn’t bad either!

This project is a partnership between Manomet Inc., the U. S. Fish and Wildlife Service, the Wildlife Conservation Society, the U.S. Geological Survey, and BP Alaska Inc.  Major funding was provided by the National Fish and Wildlife Foundation, and by donors to Manomet.