How To Count Arctic Shorebirds

One of our three projects this season is conducting surveys across the Arctic Refuge coastal plan to find out how many shorebirds are there. We do this for many reasons, primarily as part of a large and coordinated arctic-wide survey that is part of the Program for Regional and International Shorebird Monitoring or PRISM. This program developed out of the U.S. and Canadian Shorebird Plans and aims to track populations of all the shorebirds that breed in North America. We use the data to track the health of shorebird species, and also to measure increases from conservation action or decreases from threats they face. We also use the data to identify critical sites based on what percentage of the population uses them, and we need the entire population count to find out what sites have a large proportion of the population. For arctic nesting shorebirds, the best time to count them is while they are breeding, because individuals spread themselves out across the landscape and set up nesting territories where they sing and display.

Shorebird nests are incredibly well hidden, they have to be to survive the many arctic predators, especially foxes and Jaegers. That means it’s very hard to find them, so we can’t count shorebirds by counting nests. While normally quiet when we see them on migration, arctic shorebirds sing energetically and display aggressively on their nesting grounds, adding a delightful side to their otherwise demure behaviors, and also making them possible to count.

Can you see the Semipalmated Sandpiper nest in this photo?  I can’t either, and I know where it is, in a small mound in the center of the foreground.  And that’s camp in the background. Photo credit Stephen Brown/USFWS

Can you see the Semipalmated Sandpiper nest in this photo? I can’t either, and I know where it is, in a small mound in the center of the foreground. And that’s camp in the background. Photo credit Stephen Brown/USFWS

If you step a little closer, you can just make out the small opening above the eggs in the small mound in the center of the photo.

If you step a little closer, you can just make out the small opening above the eggs in the small mound in the center of the photo.

Here’s the nest, well camouflaged in the tundra.  It’s very difficult to find shorebird nests without cues from the adults.  That’s why we count the adults and not the nests. Photo credit Stephen Brown/USFWS

Here’s the nest, well camouflaged in the tundra. It’s very difficult to find shorebird nests without cues from the adults. That’s why we count the adults and not the nests. Photo credit Stephen Brown/USFWS

To find out how many shorebirds use habitats of different types across the tundra, we first categorize the many different types of tundra into classes, mostly related to how wet or dry they are. Habitats that are wetter are generally better for both shorebirds and waterfowl, but we have to visit all types to figure out how many birds are using the entire landscape. So we randomly select plots that are representative of different habitat types and visit them all during the course of our survey.

Drier upland tundra like this tussock tundra generally has fewer birds, but sometimes has some, and there are lovely views of the upper parts of the coastal plain to distract you from the ankle and knee busting terrain.

Drier upland tundra like this tussock tundra generally has fewer birds, but sometimes has some, and there are lovely views of the upper parts of the coastal plain to distract you from the ankle and knee busting terrain.

The lower parts of the coastal plain are full of wetlands like this one, and the abundant water makes for a high density and diversity of shorebirds and waterfowl.  As long as there are small higher places to nest!

The lower parts of the coastal plain are full of wetlands like this one, and the abundant water makes for a high density and diversity of shorebirds and waterfowl. As long as there are small higher places to nest!

We also survey habitats along the rivers and streams, where gravel bars are common, and where you find birds adapted to nest on gravel. Semipalmated Sandpipers are one of my personal favorites.

We saw more birds that use riverine habitats on the survey this year, like this Semipalmated Plover…

We saw more birds that use riverine habitats on the survey this year, like this Semipalmated Plover. Photo credit: Shiloh Schulte.

…and this Ruddy Turnstone, because we created a habitat strata in riverine areas to better capture this rich but relatively rare habitat type and the birds that depend on it.

…and this Ruddy Turnstone, because we created a habitat stratum in riverine areas to better capture this rich but relatively rare habitat type and the birds that depend on it. Photo credit: Shiloh Schulte.

For all these nesting shorebirds, the period when they are singing and displaying is short, usually confined to the time when they are finding mates, setting up territories, and defending their territories from others. That means the window for doing this work is very short, usually around 10 days in the early spring. It is very difficult to time the survey precisely because the onset of spring varies from year to year, and we need to plan our travel and reserve dates with a helicopter company many months in advance. This year spring came early on the tundra, so we were rushing to get our crew in place in time to see and count the birds while they were still displaying.

Because we have to cover a very large area during our survey (the coastal plain is the size of the state of Delaware), we depend on a small helicopter to access the remote plots. This year we flew with Pollux Aviation, who does an amazing job working with us and our partners at USFWS. Our pilot Nick was just great and worked with us to safely access all of our plots during the times in between the foggy weather when we could make it to our widely scattered survey areas. The helicopter is quite small, and just barely has room for the pilot and three surveyors with their gear for the day.

Ready to head out for surveys, the crew is packed in like sardines in the tiny Robinson R-44.  Good thing we all get along so well!  Photo credit Stephen Brown/USFWS.

Ready to head out for surveys, the crew is packed in like sardines in the tiny Robinson R-44. Good thing we all get along so well! Photo credit Stephen Brown/USFWS.

But even with the birds singing up a storm and doing all their displays, they aren’t always visible at any given time, so we miss some during our brief visits to each plot that last only about an hour and a half. So we need a way to correct for birds we missed, which is called a detection rate. Over the many years we have been doing PRISM surveys, we have studied some plots the same size as our survey plots very intensively, and we very cleverly call these Intensive Plots. On these plots, shorebird scientists spend the whole season carefully finding and tracking each nest, and then the rapid surveys are carried out as usual by other scientists who have no idea what birds are there, just like at our regular survey locations. From those intensive plots, we can calculate how many of each species we miss, and on average it turns out that we see and count about 80 percent of the birds on a plot. We use those data, updated each year, to calculate the total populations, including the birds we likely missed.

This female Pectoral Sandpiper is taking a break from incubation, and has a nest nearby.  You would never find the nest unless the bird shows you where it is when it returns to start incubating again, so sometimes we miss birds on our survey, and have to estimate how many we didn’t ever see.

This female Pectoral Sandpiper is taking a break from incubation and has a nest nearby. You would never find the nest unless the bird shows you where it is when it returns to start incubating again, so sometimes we miss birds on our survey and have to estimate how many we didn’t ever see. Photo credit: Shiloh Schulte.

We have now finished our PRISM surveys, and are starting the process of entering all the data. Soon we will have new population estimates, both for the Arctic Refuge coastal plain itself and also as a part of the overall population estimate for each species for the entire Arctic. As we wrap up this first project, we are very grateful to all our supporters, especially the National Fish and Wildlife Foundation, and the many private donors who provided matching gifts, for making the work possible. Next up, the crew is shifting to the second and third major projects of the season, tracking how long nests of various species survive on the tundra, and tracking their movements and habitat use after the nesting season with satellite tags. We will be reporting on those efforts soon.

 

 

Intro to the 2018 Field Season

Welcome to another exciting field season with the Shorebird Recovery Program!

This year we are again posting from two different field sites in Alaska as we work to understand what limits Shorebird populations, and which sites are most important for their long migrations.

Shiloh Schulte is working with the crew going back to the Canning River in the Arctic National Wildlife Refuge. He and the team there put geolocators on several species last year and will be holding their breath to see which birds came back to nest again this year, and then using all their tundra stealth to recapture them so we can collect their geolocators and learn vital secrets about where they have spent the past year. They will also be putting out new tags that can report their specific location by satellite. This collaborative project is led by Rick Lanctot from USFWS, together with Chris Latty of the Arctic Refuge, and continues our work started as the Arctic Shorebird Demographics Network. Shiloh will post soon to introduce this year’s team working at the Arctic Refuge and share the beginning of their story. So far it has been so cold and snowy on the distant north slope that the team has been waiting in Fairbanks for the weather to improve and the birds to arrive!

Meanwhile, another new project is just getting started in several National Parks and Wildlife Refuges in northwest Alaska. The National Park Service wanted to know if any Spoon-billed sandpipers, one of the world’s most endangered shorebirds normally only found across the Bering Strait in Russia, might be using similar habitats in Alaska. We will be doing surveys as part of the ongoing international collaboration called the Program for Regional and International Shorebird Monitoring to both search for this rare species, and also document what other shorebirds are using these areas. We are again working with Rick Lanctot as well as colleagues at the National Park Service on this project and will be based in Kotzebue Alaska. Brad Winn and Metta McGarvey are returning to work on this new project, and all three of us will be updating you on how the project is unfolding, and the interesting encounters we have in this region.

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Flying over the Alaska Range while heading north through rugged mountains laced with glaciers.

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Once north of the mountains, the vast wetlands of the coastal tundra stretch beyond view.

 

PRISM Surveys of Arctic Nesting Shorebirds

The purpose of our work in the Yukon Delta National Wildlife Refuge is to collect data for PRISM (the Program for Regional and International Shorebird Monitoring). PRISM is a large-scale international collaboration of researchers throughout the Western Hemisphere who are using a standardized protocol for collecting data with three main goals:  1) estimating the breeding populations of arctic, temperate, and neotropical shorebirds; 2) monitoring trends in shorebird population size, especially large population declines over 20 year periods; and 3) setting conservation priorities and assisting local wildlife managers in meeting their shorebird conservation goals.

 

Kuzilvak Wetlands Aerial

This aerial view approaching our campsite near Kuzilvak Mountain in the Yukon Delta National Wildlife Refuge gives a glimpse of the tremendous wetland resources in this vast region that shorebirds rely on for nesting. Photo by Metta McGarvey.

 

Manomet’s Shorebird Recovery Program has been a partner in collecting data for PRISM in the arctic since its inception in 2001.  While PRISM has many government agencies participating, funding has always been hard to come by and our partnership as an NGO raising private donor resources has been essential for the program.  Our generous donors are essential for ensuring that we have good data on shorebird populations on which to plan their recovery.

As I described in the last podcast, we collect PRISM data using a double sampling method. First, we conduct rapid surveys of a large number of randomly selected plots to estimate the number of breeding shorebirds in important regions like the Yukon Delta, the Arctic National Wildlife Refuge, and the Teshekpuk Lake region of the National Petroleum Reserve-Alaska. This year, as in past years, PRISM rapid surveys in the arctic require the use of helicopters during a short two-week window when the birds are at their most active setting up territories, attracting mates, and establishing their nests. Because the Yukon Delta National Wildlife Refuge is the size of Maine, we have three helicopter crews conducting rapid surveys this year so that we can cover the vast landscape.

We carefully train our observers to hone their skills in rapidly detecting shorebirds by sight and sound because you often get only a small glimpse of a bird as it hurries by or hear its breeding song from a distance and obscured by the constant wind.  This year we had the privilege of having Brian McCaffery, who worked at the Yukon Delta over many years as a biologist and the head of the biology program, partner with me to assemble a set of exemplary shorebird songs from both his personal collection and from Cornell Laboratory of Ornithology’s McCaulay Library of Natural Sounds.  Brian’s deep expertise in sorting out the many complex vocalizations of breeding shorebirds was extremely helpful to the crew, and we were very grateful for his support with the training and also with planning the surveys.

 

Brian McCaffery, one of the foremost experts on shorebirds of the Yukon Delta, teaching a class on sound identification of breeding shorebirds during our training in Anchorage before the start of the surveys.  He was assisted by Bob Gill and Brad Winn.  Photo by Metta McGarvey.

Brian McCaffery, one of the foremost experts on shorebirds of the Yukon Delta, teaching a class on sound identification of breeding shorebirds during our training in Anchorage before the start of the surveys. He was assisted by Bob Gill and Brad Winn. Photo by Metta McGarvey.

 

We have also set up two longer-term camps where surveyors conduct intensive surveys on plots that are visited daily throughout the breeding period of four to six weeks, with the goal of finding every nest over the entire period. These intensively surveyed plots will also have a rapid survey conducted on them by the helicopter crews who don’t know anything about what is nesting there when they start. By comparing the rapid estimate of how many breeding shorebirds are on the plots with the data gathered over the entire breeding season by the intensive surveyors, we adjust the detection rates of the rapid surveyors. Because a rapid survey only lasts one hour and thirty-six minutes, we know each rapid survey misses a percentage of the shorebirds breeding on each rapid plot; this comparison allows us to better estimate the likely number of breeding shorebirds on each rapid plot and thereby better estimate population sizes across the huge landscape being surveyed.

As always, finding shorebird nests in the vast tundra is a challenge.  The photos below show the incredible camouflage chosen by a pair of Black-bellied Plovers nesting near camp.

 

Photo3A BBPL Nest 2016

This Black-bellied Plover nest is situated on bare ground, but it is perfectly camouflaged; Metta’s hand gives perspective on the size of the eggs, which are unusually large compared to most smaller shorebirds. Photos by Metta McGarvey

This Black-bellied Plover nest is situated on bare ground, but it is perfectly camouflaged; Metta’s hand gives perspective on the size of the eggs, which are unusually large compared to most smaller shorebirds. Photos by Metta McGarvey

Stepping back just a few feet shows how camouflaged the nest is among the background of lichens and tundra on which it was laid. Photo by Metta McGarvey

Stepping back just a few feet shows how camouflaged the nest is among the background of lichens and tundra on which it was laid. Photo by Metta McGarvey

 

Dunlin nests, like this one I found on a rapid survey plot, are equally camouflaged.  Up close the nest is easy to see, but if you step back just a bit it is superbly concealed, and from a few yards away it blends seamlessly into the landscape.  You can see from this why we survey during the brief period when the birds are setting up nests and advertising their territories with songs and displays!

 

Photo4A DUNLNestPhoto4B DUNLNest

This Dunlin nest is visible from up close, but disappears when you step back just a bit, which helps them avoid predators looking for a tasty meal, and also makes surveying shorebirds a real challenge. Photos by Stephen Brown.

This Dunlin nest is visible from up close, but disappears when you step back just a bit, which helps them avoid predators looking for a tasty meal, and also makes surveying shorebirds a real challenge. Photos by Stephen Brown.

 

We will write more soon about the incredible diversity of wildlife we see on the tundra during our surveys and will also have updates from the other crews surveying in other parts of the Refuge.