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California’s Tricolored Blackbird is Running Out of Room

All About Birds - Tue, 03/12/2019 - 14:17

From the Spring 2019 issue of Living Bird magazine. Subscribe now.

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Seeing more hawks in your yard? It’s not your imagination

All About Birds - Thu, 03/07/2019 - 14:15
A young Sharp-shinned Hawk at a feeder. Photo by Kevin Rosinbum via Birdshare.

Raptors—especially Cooper’s Hawks and Sharp-shinned Hawks—have become a familiar presence at urban and suburban feeders around North America. But it wasn’t always this way.

In a 2017 retrospective of Project FeederWatch results, we noted that Cooper’s Hawks increased their presence fourfold at FeederWatch sites over the past two decades. The agile accipiters occurred at just 6% of feeders in 1989, but by 2016 had increased to around 25% of feeders. Cooper’s Hawks have historically been thought of as a rural species, picking songbirds from branches in surprise attacks in the woodlands and forests. But one clear factor in the surge of FeederWatch reports has been their expansion into suburban and urban areas.

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Scientists from the University of Wisconsin-Madison and the Cornell Lab of Ornithology took these results and went further, trying to find out what might be behind these increases. They looked at 21 years of Project FeederWatch data (1996–2016) from winters in the greater Chicago area, a period in which accipiter sightings increased from 26% to more than 60% of all feeders.

The results, published in November 2018 in the Proceedings of the Royal Society B, suggest that the main reason Cooper’s Hawks (as well as their petite doppelgangers, Sharp-shinned Hawks) have spread into these new environments is an increase in prey availability.

Data from 554 Project FeederWatch sites in the greater Chicago area showed that Cooper’s and Sharp-shinned Hawks visited 27% of sites (around 150) in 1996, compared with 63% (around 350) in 2016. Graphic by Bartels Science Illustrator Jessica French.

The team went into the study thinking that areas with more tree cover, fewer paved surfaces, and more prey availability would see an increase in hawks—basically, the image of a leafy suburban neighborhood with room for both songbirds and hawks. In the early years of the data, this held true, and hawks were less likely to occur in heavily urbanized areas with more paved surfaces. But then something interesting happened.

Eventually, hawks moved into (and stayed in) moderately or heavily urbanized areas, provided there was enough prey. (The researchers calculated prey abundance using Project Feederwatch data.) By the end of the study period, hawks were actually somewhat more likely to occur in places with fewer trees.

The researchers speculated that since the FeederWatch data represent the winter months, when hawks were not nesting, their primary concern was finding prey rather than nesting habitat. Since landscapes with fewer trees often have higher human populations, they might have higher numbers of bird feeders as well. By attracting and concentrating feeder birds, these areas might provide the best winter food resources for hawks as well as songbirds.

This sounds like good news for hawks, but does it mean backyard feeders are becoming more dangerous for songbirds? Emma Greig, project leader for FeederWatch, says that it’s complicated.

Take down feeders, or leave them unfilled, for a couple of weeks to encourage hawks to disperse. Sharp-shinned Hawk by Hanako228 via Birdshare.

“As the authors point out, previous studies have shown that a lot of the birds that these hawks are taking in urban areas are invasives such as pigeons and starlings – so that could actually help native species.” Greig points out that many of the native prey species for these hawks—American Goldfinches, Dark-eyed Juncos, Northern Cardinals, and Mourning Doves, for example, all have stable populations.

“It doesn’t mean you should just let a predator wreak havoc at your feeder for weeks on end…sometimes taking a feeder down to discourage frequent attacks is a good strategy,” Greig says. “At the same time, regular visits from Cooper’s Hawks and sharpies aren’t necessarily a bad thing.” And when you’re out and about—even if you’re downtown—keep an eye out for a slim, long-tailed shape gliding inconspicuously through streets and parks. It could be one of these newly numerous urban accipiters.

Reference

McCabe, J.D. et al. (2018). Prey abundance and urbanization influence the establishment of avian predators in a metropolitan landscape. Proceedings of the Royal Society B 285 (1890).

Climate Change is Leading to Unpredictable Ecosystem Disruption for Migratory Birds

All About Birds - Tue, 03/05/2019 - 13:02

Climate change is leading to unpredictable ecosystem disruption
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Black-and-white Warbler
In the latter half of this century, migrants such as the Black-and-white Warbler may experience climate extremes unlike any in their history. Photo by Kelly Colgan Azar.

Study: Climate Change is Leading to Unpredictable Ecosystem Disruption for Migratory Birds

For release: March 5, 2019

Ithaca, NY—Using data on 77 North American migratory bird species from the eBird citizen-science program, scientists at the Cornell Lab of Ornithology say that, in as little as four decades, it may be very difficult to predict how climate change will affect migratory bird populations and the ecosystems they inhabit. Their conclusions are presented in a paper published in the journal Ecography.

“Climates have natural variation and we’re moving rapidly into territory where the magnitude of climate change will consistently exceed this variation,” says lead author and Cornell Lab researcher Frank La Sorte. “There will be no historic precedent for these new climates, and migratory bird populations will increasingly encounter ‘novel’ climatic conditions. The most likely outcome will be a period of ecological disruption as migratory birds and other species try to respond or adapt to these new conditions.”

Cornell Lab scientists generated new climate models incorporating multiple sources of data. This produced a timeline indicating when and where migratory bird populations are likely to be significantly affected by novel climates during each phase of their annual life cycles. It’s not that far off:

— Last 40 to 50 years of this century. During this period, migrants such as the Black-and-white Warbler are likely to first experience novel climates on their tropical wintering grounds (regions south of Florida) and also during the late summer on their breeding grounds in the North American temperate zone (above the nation’s midsection).

— First 50 years of the next century. This is when novel climates are likely to emerge for birds that winter in the subtropics—the southern half of the U.S.

The study authors conclude that by the middle of the next century migratory bird populations will experience novel climates during all phases of their annual life cycles.
animation of emerging novel climates
Map shows where and when novel climates are likely to emerge based on projections from the International Panel on Climate Change. Animation by Frank La Sorte, Cornell Lab of Ornithology.

La Sorte and co-authors considered minimum and maximum temperatures, and precipitation in the Western Hemisphere, week by week, for 280 years, from 2021 through 2300, under the worst-case scenario: continued high levels of greenhouse gas emissions. La Sorte says this is the first study to use a combination of climate variables to estimate when novel climates will first emerge, and it is the first study to examine the full annual cycle implications for a large number of migratory bird species.

Yellow Warbler
Yellow Warblers breed in the temperate zone of North America and are among the species likely to encounter novel climates in the latter half of this century. Photo by Kelly Colgan Azar. “It’s not surprising that novel climates will be first encountered in the tropics,” says La Sorte. “There’s little variation in tropical climates, so even a small change in climate can generate highly novel conditions. It is surprising to find that on these species’ breeding grounds, novel climates will emerge roughly 40 to 50 years earlier during the second half of the breeding season. This is a critical phase of these species’ life cycle when adult and juvenile birds are transitioning from breeding to migration.”

The three data sources used for the study were 13 years of observations from the eBird program (2004-2016), climate projections from the most recent International Panel on Climate Change report, and NOAA data used to estimate climatic variation over a 60-year period. What constitutes a “novel” climate will depend on each region’s historical norms for that season.

“One reason we are considering novel climates is that current ecological projections under climate change tend to be unrealistic,” explains La Sorte. “We can’t reliably predict how birds or other species will respond to novel climates. In this study, we document when in the future this uncertainty is likely to become a significant factor that could adversely affect migratory bird populations.”

Reference:
Frank A. La Sorte, Daniel Fink, Alison Johnston (2019) Time of emergence of novel climates for North American migratory bird populations. Ecography.

This research was funded by The Leon Levy Foundation, The Wolf Creek Charitable Foundation, NASA, a MIcrosoft Azure Research Award, and the National Science Foundation.
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Editors: Download images and animation for use with stories about this research.

Media Contact:
Pat Leonard, Cornell Lab of Ornithology, (607) 254-2137, pel27@cornell.edu

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The Cornell Lab of Ornithology is a membership institution dedicated to interpreting and conserving the earth’s biological diversity through research, education, and citizen science focused on birds.

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Fieldwork in East Africa: Cooperative Breeding in Superb Starlings [Video]

All About Birds - Tue, 03/05/2019 - 10:05
Superb Starlings help each other raise young in the unpredictable climate of East Africa, an intriguing behavior known as cooperative breeding. hbspt.cta.load(95627, 'a8fe3c9a-217b-40fd-b1ff-2bb76ebe2cf3', {}); --> hbspt.cta.load(95627, '394b2cc2-4447-4677-b18b-d2f2de5b57cd', {}); -->

In April, 2018, I  traveled to the Mpala Research Centre in central Kenya as part of an Ivy Expedition, along with three other Cornell students—Facundo Fernandez-Duque, Rachael Mady, and Sarah Toner. Our mission was to collect photographs, videos, and audio recordings of species underrepresented in the Cornell Lab’s Macaulay Library. But we also met up with Shailee Shah ‘14—a Cornell alumna and current Columbia Ph.D. student who is studying the fascinating breeding ecology of Superb Starlings.

Our team filmed Shailee throughout several days of data collection in the field with the ultimate goal of creating a short film about her work. One of the most challenging parts of the filming process was actually getting good footage of Superb Starlings—the focal species of the film! It seemed as if whenever we would finish setting up the camera and tripod to start recording, the flock of starlings would immediately fly out of frame. It was almost as if they knew we were trying to film them. Fortunately, Shailee was a much more cooperative subject as she answered our questions and described the nature of her work on cooperative breeding.

After returning to the U.S., I turned to producers in the Cornell Lab’s Conservation Media program for mentorship as I edited this piece together. I learned to use robust video editing software and bolstered my skills in multimedia productions; I hope to keep improving these skills as I move forward in life. As an emerging scientist myself, I hope to show my audience about the wonders of pursuing field research, and aim to inspire young scientists to follow in Shailee’s footsteps.

Birding Festivals and Events

All About Birds - Fri, 03/01/2019 - 09:37
googletag.cmd.push(function () { googletag.defineSlot('/106885985/aab_default', [300, 250], 'div-dfp-slot1').addService(googletag.pubads()); googletag.defineSlot('/106885985/aab_default_bottom', [300, 250], 'div-dfp-slot2').addService(googletag.pubads()); googletag.defineSlot('/106885985/aab_leaderboard', [728, 90], 'div-dfp-leaderboard').addService(googletag.pubads()); googletag.pubads().setTargeting('pid', ['/feed/']).setTargeting('url', ['aab']); googletag.enableServices(); }); googletag.cmd.push(function () { googletag.display('div-dfp-slot1'); }); googletag.cmd.push(function () { googletag.display('div-dfp-slot2'); }); Upcoming Bird Festivals and Events

A great way to enjoy bird watching is by going to festivals—they’re organized to get you to great birding spots at a great time of year, and they’re a great way to meet people. Experts and locals help you see more birds, and you’ll meet other visitors who share your hobby. While you’re there, keep an eye out for Cornell Lab representatives, as we do attend several festivals each year.

To list your festival on this page, please contact our advertising manager:
Susanna Lawson
phone: 434-983-1771
fax: 434-983-1772
svl22@cornell.edu

Festivals by Location

Click on a pin for details, contact information, and festival website. You can zoom and scroll the map to get a closer look at the pins.

Festivals by Date

Click on an event URL for full details. Scroll down the list to see all scheduled events.

In March, Win a Spot in the Cornell Lab’s Sparrow Identification Course

All About Birds - Fri, 03/01/2019 - 08:00

Win a free spot in the Cornell Lab’s sparrow identification course
By Team eBird March 1, 2019
Swamp Sparrow
Swamp Sparrow Melospiza georgiana
© Evan Lipton
Macaulay Library
eBird
We’re excited to partner with the Cornell Lab’s Bird Academy to offer a suite of exciting educational resources in thanks for your eBirding: in March, every eligible checklist that you submit gives you a chance to win free access to an upcoming course on sparrow identification.

Ten lucky eBirders will get this course for free from their March eBirding! If you like taking part in the eBirder of the Month Challenges, here are even more excuses to motivate yourself to get out birding. Each month of 2019 will feature a different Bird Academy course offering—tune in at the start of April to see what’s on tap for next month.

March 2019 eBirder of the Month Challenge

All About Birds - Thu, 02/28/2019 - 09:08

March eBirder of the Month Challenge
By Team eBird February 28, 2019
Chestnut-breasted Munia
Chestnut-breasted Munia Lonchura castaneothorax
© Marc Gardner
Macaulay Library
eBird
This month’s eBirder of the Month challenge, sponsored by Carl Zeiss Sports Optics, encourages precise eBirding through eBird Mobile. On iOS and Android, the free eBird Mobile app allows you to track your checklists using the device GPS—providing unprecedented detail in your eBird checklists on where exactly you went birding. You can just focus on birding, and let the app do the work! The eBirder of the Month will be drawn from eBirders who submit 20 or more eligible checklists with eBird Mobile ‘tracks’ in March. Checklists must be for observations during this month; not historical checklists entered during March. Winners will be notified by the 10th of the following month.

If you haven’t tried eBird Mobile before, there’s no better time than now. Unique My eBird stats, easy Quick Entry shortcuts that make entering data faster than pen & paper, and automated GPS tracks that make eBirding even easier. Almost 70% of all eBird data are entered on mobile now, and that number grows with each passing month. Learn how to get started with eBird Mobile here.

eBird Mobile tracks are leading the way to a host of exciting future eBird tools. Imagine going to a hotspot, and being able to see an overlay of where eBirders have been in the past—a way to understand how to bird the location as well as what’s present. Or not even having to choose a location when you’re eBirding, and instead just letting the app suggest where you were and allowing you to just confirm. These tools, as well as numerous research impacts, will all be possible as more eBirders use eBird Mobile.

Each month we will feature a new eBird challenge and a set of selection criteria. The monthly winners will each receive a new ZEISS Conquest HD 8×42 binocular. Don’t forget about the 2019 Checklist-a-day Challenge. Can you submit 365 eligible checklists this year?

Carl Zeiss Sports Optics is a proven leader in sports optics and is the official optics sponsor for eBird. “We are thrilled to continue our partnership with the Cornell Lab of Ornithology and support the vital scientific data being collected by dedicated eBirders.” – Richard Moncrief, Birding and Nature Observation Segment Manager at Carl Zeiss SBE

Jane Johnson, January 2019 eBirder of the Month

All About Birds - Tue, 02/26/2019 - 14:56

By Team eBird February 26, 2019

Please join us in congratulating Jane Johnson of Tofte, Minnesota, winner of the January 2019 eBird Challenge, sponsored by Carl Zeiss Sports Optics. Jane’s name was drawn randomly from 1,900 eBirders who submitted at least 1 eligible eBird checklist in January, and also took the eBird Essentials course. Jane will receive a new ZEISS Conquest HD 8×42 binocular for her eBirding efforts. Here’s Jane’s birding story:

We always had bird feeders when I was growing up. My first memory of recording bird data was for a junior high science project where I compared weather conditions with the number of birds at our feeders. I wish there had been eBird back then!

I worked as a medical social worker in Minneapolis and St Paul, Minnesota for 30 years, during which birding was a great stress reliever. I volunteered with Osprey and Trumpeter Swan reintroduction projects there.

When we retired, my husband, Ken, and I moved to Tofte, MN, on the North Shore of Lake Superior. This is an outstanding birding area, especially during migration. One of the great joys of retirement is that I get to go birding every day!

This is when I discovered eBird. Cook County, MN was an under-reported area. It seemed like most of the submissions were for the unusual species seen here. I decided to eBird regularly to provide more data. The barcharts and rare bird alerts are fascinating.The monthly challenges encourage me to think about my birding in different ways. I also love participating in Project FeederWatch. During the winter, after the black bears have gone into hibernation, Ken tends 15 suet and seed feeders around our house. Where we live, the closest movie theater or shopping mall is 90 miles away, so birding is our entertainment!

For the past 4 years, Ken and I have volunteered at nearby Sugarloaf Cove Nature Center. I help with their bird banding program and we both fill feeders there in the winter. Banding is wonderful for improving my identifications skills. There’s nothing like seeing warblers, vireos, flycatchers and thrushes in the hand . . . and, it’s given me a fun group of “bird nerd” friends!

In January, much of my birding was feederwatching. Snow depths around 4 feet, daytime high temperatures of below zero Fahrenheit and a recent knee replacement kept me from going too far. I kept in mind the eBird instruction – “we want your boring checklists.” [Team eBird note: We don’t think there is such a thing as a ‘boring checklist’! Every sighting counts.] Winter highlights have been daily Pileated Woodpecker visits, a frequent Northern Shrike and a male Ruffed Grouse displaying this past December.

Ken bought me my first pair of good binoculars at least 25 years ago. I’m thrilled to have won this challenge and to be receiving an even better pair. Thanks to eBird and Zeiss for this wonderful gift!

How Changes in Temperature and Rainfall Affect Nesting Bluebirds and Swallows

All About Birds - Tue, 02/26/2019 - 11:21

Buckeye Birds Track Temperature And Precipitation
Photo © Tonya Roth
by Robyn Bailey, NestWatch Project Leader
In America’s heartland, farmers rely on birds to help suppress agricultural pests. In fact, it’s why many of them install nest boxes around their farms. If climate change is predictably causing nesting birds to start nesting earlier in the spring as temperatures warm (as several studies suggest), this could mean that insectivorous birds will become out of sync with their insect prey. That wouldn’t be good for either the birds or the farmers. Considering this, researchers set out to test which climate variables most correlated with the onset of egg-laying in both Eastern Bluebirds and Tree Swallows in Ohio. In a new study published in American Midland Naturalist, Jesse Sockman and Jason Courter of Malone University analyzed 4,417 Ohio nest records submitted from 2000-2015 to NestWatch. Bluebirds in Ohio, as in most parts of their range, are double-brooded, so only their first nests of the year were used in this study. Tree Swallows are single-brooded and therefore any Tree Swallow nest could be utilized.

Tree Swallow Eggs
Tree Swallow Eggs
A feathery nest of a Tree Swallow contains two eggs, with more to come.

Photo © Sheryl Boser

SUNNY DAYS OR RAIN DELAYS?
As expected, both species started nesting earlier in more southerly parts of the state, but latitude alone did not explain the variation in when birds start to lay eggs. The study concludes that Eastern Bluebird first-egg-dates were earlier in warmer springs but later in wetter springs. Tree Swallows, on the other hand, did not seem to be impacted by spring temperature as much, but, like bluebirds, they did initiate egg-laying later in wetter springs. Both species, fortunately, did overlap with insect pest life cycles in ways that would help control the pests. Birds want to be nesting when the most prey are available to feed their youngsters, and it appears that they are still within this range in Ohio.

Timing Is Everything
Timing Is Everything
An Eastern Bluebird nestling awaits a meal, while its siblings struggle to break free from their shells.

Photo © Kimberlie Sasan

INSECTS, BIRDS, AND THE FUTURE
Tree Swallows seemed to be more closely tracking a measure of accumulated heat known as “growing degree-days”; whereas Eastern Bluebirds did not coincide with this measure of cumulative warmth. Growing degree-days (as opposed to calendar day) is a temperature-based concept familiar to most farmers because it provides a measure of seasonal crop progress and a guide for timing farm management activities such as pesticide and herbicide application. Insect pests such as the Eastern tent caterpillar, gypsy moth, inkberry leafminer, and lilac borer (among others) are significant agricultural pests which impact growers economically, and their emergence maps well onto the growing degree-day concept. If birds can act as biological controls and suppress the crop pests, farmers may benefit from increased avian diversity on their property. However, climate models are predicting warmer annual temperatures and wetter springs in the study region over the next century, further complicating the interpretation of these results. For example, could temperature-related advancements be offset by precipitation-related delays in nesting? Or are Eastern Bluebirds and Tree Swallows actually tracking some unmeasured variable such as insect abundance?

One of the study’s authors, Dr. Jason Courter, explains that it’s very difficult to predict how a changing climate will affect birds. He did, however, express his gratitude to NestWatchers for their help in this study, saying “We are grateful for the countless volunteers who have faithfully submitted nesting observations over these 16 years through NestWatch and made a project of this magnitude possible.” Indeed, thank you NestWatchers for providing thousands of nests each year to support studies like this!

Reference:
2018. Sockman, J., and J. Courter. The impacts of temperature, precipitation, and growing degree-days on first egg dates of Eastern Bluebird (Sialia sialis) and Tree Swallow (Tachycineta bicolor) in Ohio. American Midland Naturalist 180(2): 207-215. doi: https://doi.org/10.1674/0003-0031-180.2.207.

Great Gray Owls Show Resilence After a Megafire in California

All About Birds - Tue, 02/12/2019 - 13:33

Editor’s note: The following press release describes a new article in The Condor: Ornithological Applications, a journal of the American Ornithological Society.

A new study to be published in The Condor: Ornithological Applications shows that certain endangered owls may continue to persist and even flourish after large forest fires.

Throughout western North America, longer, hotter fire seasons and dense fuels are yielding more frequent, larger, and higher-severity wildfires. Spurred by climate change, megafires in the region are often characterized by unusually large, continuous patches of high-severity fire in mature forests.

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The Great Gray Owl is an endangered species in California. The Great Gray Owl population was recently estimated at fewer than 100 pairs in the state. The 2013 Rim Fire burned 104,000 acres in Yosemite National Park and Stanislaus National Forest, making it the largest recorded fire in California’s Sierra Nevada region. The fire perimeter contained 23 meadows known to be occupied by Great Gray Owls during the decade prior to the fire, representing nearly a quarter of all known or suspected territories in California at the time.

Researchers analyzed 13 years of Great Gray Owl detection data (from 2004 to 2016) from 144 meadows in the central Sierra Nevada, including meadows inside and outside the Rim Fire perimeter in Yosemite National Park and on Stanislaus National Forest.

During three years of surveys after the fire, Great Gray Owls were found at 21 of 22 meadows surveyed within the fire perimeter that were occupied during the decade prior to the fire.  The researchers surveyed 144 meadows in at least one year prior to the 2013 Rim fire; 54 of these were also surveyed during at least a year after the fire. Researchers found Great Gray Owls at least once at 89 meadows, with detections at 68 of 92 meadows in Yosemite National Park, and at 21 of 52 meadows outside of National Parks.

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Rather than decreasing after the fire, persistence of owls at meadows actually increased on both National Park Service and other lands, while colonization rates exhibited no significant change. Great Gray Owls appear to have been largely resilient to effects of the Rim Fire during the three years after it burned.

Stable occupancy and increased site persistence after fire suggest an overall resilience to the effects of the fire during the three years after it burned. Any negative effects stemming from loss in nesting habitat appear to have been counterbalanced by other factors. Because Great Gray Owls most typically nest in the rotting remains of substantially deteriorated trees, fire could potentially enhance Great Gray Owl nesting habitat by killing large trees that become suitable nesting structures. Another positive effect of fire could be to enhance conditions for meadow-dwelling rodent populations that constitute the primary prey of Great Gray Owls.

Many researchers and land managers believe that forest thinning to reduce fire risk is critical to ensure the persistence of wildlife species associated with these forests. But this research suggests suggest forest resilience treatments are not needed to protect Great Gray Owls, and conservation efforts might be better directed to other needs of the species.

“The Rim fire looked like a worst-case scenario for California’s Great Gray Owls, because it was pretty much centered on the heart of the population, and affected up to a quarter of all the territories in California,” said the paper’s lead researcher, Rodney B. Siegel. “Our discovery that the owls remained and in many cases even continued to nest at the burned sites after the fire is good news for Great Gray Owls. We need to keep monitoring this population to find out if the owls will continue to use these burned sites over the longer-term, as the trees that were killed by the fire deteriorate and eventually fall.”

About the journal: The Condor: Ornithological Applications is a peer-reviewed, international journal of ornithology, published by the American Ornithological Society.

Reference

Siegel, R.B., et al. 2019. Short-term resilience of Great Gray Owls to a megafire in California, USA. The Condor: Ornithological Applications 121(1).

New Hope for Newell’s Shearwaters and Hawaiian Petrels on Oahu, Hawaii

All About Birds - Tue, 02/12/2019 - 13:17

Editor’s note: The following press release describes a new article in The Condor: Ornithological Applications, a journal of the American Ornithological Society.

The two seabird species unique to Hawaii, Newell’s Shearwaters and Hawaiian Petrels, are the focus of major conservation efforts—at risk from habitat degradation, invasive predators, and other threats, their populations plummeted 94% and 78% respectively between 1993 and 2013. However, a new study in The Condor: Ornithological Applications offers hope of previously undetected colonies of these birds on the island of Oahu, from which they were believed to have vanished by the late 1700s.

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Shearwaters and petrels nest colonially in crevices, burrows, and under vegetation at mid to high elevations. They currently breed on other Hawaiian islands including Kauai and Maui, but were both believed to have extirpated from Oahu prior to European contact in 1778; biologists believed that occasional records from the island were birds thrown off-course at night by city lights.

Pacific Rim Conservation’s Lindsay Young and her colleagues used a spatial model based on elevation, forest cover, and illumination to identify potential suitable breeding habitat for both species on Oahu, then deployed automated acoustic recording units at 16 sites on the island to listen for the birds’ calls in 2016 and 2017, accessing remote mountain locations via helicopter. To their surprise, they detected petrels at one site and shearwaters at two sites.

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“We were doing a statewide survey for these species for the U.S. Fish and Wildlife Service as part of recovery action planning, but Oahu was not initially included as one of the sites to survey, since evidence suggested they weren’t there,” says Young. “Since we’re Oahu-based, we thought we would at least put a few recording units out to see if there was anything. And we were surprised, to say the least, that we not only had calls detected, but detected both species across two years.”

These could be the last survivors of remnant breeding populations on Oahu, or they could be young birds from other islands that are searching for mates and breeding sites. “Either way, it gives us hope that we will be able to use social attraction—that is, using calls and decoys—to attract them nest on an island where they were once abundant,” says Young. Oahu birds could help boost connectivity between individual island populations and provide extra insurance in case any one island’s seabird population is decimated by an event such as a hurricane. As petrel and shearwater numbers continue to decline, protecting Hawaii’s remaining seabirds remains a major conservation priority in the region, and the possibility that they’re continuing to breed on Oahu provides new reason for optimism.

About the journal: The Condor: Ornithological Applications is a peer-reviewed, international journal of ornithology, published by the American Ornithological Society.

Reference

Young, L.C., et al. 2019. Evidence of Newell’s Shearwaters and Hawaiian Petrels on Oahu, Hawaii. The Condor: Ornithological Applications 121(1).

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