Link Blog – August 20, 2015


American Birding Expo | Video

  • Buy Optics from Eagle Optics, Get a Discounted ABA Membership! « ABA Blog 081515
    Our good friends at Eagle Optics are once again offering a fantastic deal for those interested in purchasing a new pair of binoculars. With the purchase of one of a select list of binoculars at a variety of price points, you can get an ABA membership – usually $45 – for the low price of $15. This special price is available for new members or for current members looking to renew.
  • ABA Blog | American Birding Association
    Nate Swick is the editor of the American Birding Association Blog. A long-time member of the bird blogosphere, Nate has been writing about birds and birding at The Drinking Bird since 2007, but can also be found writing regularly at 10,000 Birds. In the non-digital world, he’s an environmental educator and interpretive naturalist. Nate lives in Greensboro, North Carolina, with his wife, Danielle, and two young children, who are not yet aware that they are being groomed to be birders.
  • Birds and Brews – M*ch*g*n Still Sucks – by Chris ~ Rogue Birders 081915
    Christopher Collins: “Growing up in an OSU family in Columbus, OH I was taught that there is nothing good about that state up there. That I should avoid anyone and anything that hails from there. Recently I have had two experiences that prove that good things can come from even the very worst of places. | The first was during the Biggest Week in American Birding. Jeremy, Alex, Sarah, and I were all working on a “Big Day” in Lucas County to boost Jeremy and Alex’s Ohio lists for the year, and to celebrate my birthday. A message came in via Facebook, “Kirtland’s Warbler at Oak Openings!” A lifer for all of us. We hopped in the car and were off! To this day it still makes Alex uncomfortable to talk about that journey. He swears we almost died two or three times. I was driving, and I don’t remember that at all. Regardless, we made it to the park unscathed. We followed the crowd to the spot where the bird was being seen and quickly got bins and cameras on it. Though the warbler stayed mainly deep in the tree, hidden by leaves, it would occasionally make an appearance in the open allowing for some great photo opportunities. Lifer!”
  • AOU & COS Publications – Stable hydrogen isotopes identify leapfrog migration, degree of connectivity, and summer distribution of Golden Eagles in eastern North America 8/2015
    [Nelson et al 2015] Abstract: Knowledge of the distribution and movements of populations of migratory birds is useful for the effective conservation and management of biodiversity. However, such information is often unavailable because of the difficulty of tracking sufficient numbers of individuals. We used more easily obtained feather stable hydrogen isotope ratios (δ2H) to predict the summer grounds of the small, threatened, and migratory population of Golden Eagles (Aquila chrysaetos) in eastern North America. We then identified summer locations and the extent of migratory connectivity for this population. We collected δ2H (δ2Hf), stable carbon isotope (δ13C), and stable nitrogen isotope (δ15N) data from the body feathers of 47 juvenile, subadult, and adult Golden Eagles. Values of δ13C and δ15N suggested that all but 2 birds obtained food from terrestrial-based food webs and therefore that δ2H data were appropriate for inferring the geographic region of molt for the majority of birds. There was relatively large interfeather variation in the δ2H values of subadults vs. adults, suggesting that these groups molted at different times and places. The most negative δ2Hf values from birds with known summering grounds exhibited (1) a negative correlation with their summering latitude, and (2) a positive correlation with amount-weighted δ2H values of May–August precipitation at the summer location. These data validate the use of δ2Hf values for inferring the summer locations of Golden Eagles of unknown origin. Likelihood-of-origin maps derived from δ2Hf values revealed that (1) the majority of birds spent the breeding season in central Québec and Labrador, and (2) birds that wintered at southern latitudes, from approximately northern Alabama to southwestern Virginia, migrated about twice the distance of birds that wintered at northern latitudes, from Pennsylvania to New York. We observed a positive relationship between δ2Hf values and the latitude of the wintering location, which, along with the likelihood-of-origin maps, revealed moderate patterns of leapfrog migration and migratory connectivity.
  • Migratory patterns of eastern Golden Eagle population revealed | EurekAlert! Science News 081215
    Eastern North America is home to a small population of Golden Eagles (Aquila chrysaetos), but despite their potential vulnerability to habitat loss and other threats, little information has been available on the patterns of their annual migration. One big question is whether or not they exhibit “migratory connectivity,” where individuals from the same breeding area also migrate to the same wintering area; strong connectivity means that a population is divided into small subpopulations that are especially vulnerable to environmental changes. For a study forthcoming in The Condor: Ornithological Applications, authors David Nelson of the University of Maryland Center for Environmental Science, Todd Katzner of the U.S. Geological Survey (formerly West Virginia University), and colleagues traced individual eagles’ movements through isotopes in their feathers to identify their breeding areas and to assess the population’s migratory connectivity. They found that eastern Golden Eagles exhibit a moderate degree of what’s known as “leapfrog migration”: the birds that bred farthest north also spent the winter farthest south, “leapfrogging” over others in the middle. | “Stable hydrogen isotopes identify leapfrog migration, degree of connectivity, and summer distribution of Golden Eagles in eastern North America” will be available August 12, 2015 at http://www.aoucospubs.org/toc/cond/117/3.
  • AOU & COS Publications – Variables associated with detection probability, detection latency, and behavioral responses of Golden-winged Warblers (Vermivora chrysoptera) 8/2015
    [Aldinger and Wood 2015]Abstract: Detection probability during point counts and its associated variables are important considerations for bird population monitoring and have implications for conservation planning by influencing population estimates. During 2008–2009, we evaluated variables hypothesized to be associated with detection probability, detection latency, and behavioral responses of male Golden-winged Warblers in pastures in the Monongahela National Forest, West Virginia, USA. This is the first study of male Golden-winged Warbler detection probability, detection latency, or behavioral response based on point-count sampling with known territory locations and identities for all males. During 3-min passive point counts, detection probability decreased as distance to a male’s territory and time since sunrise increased. During 3-min point counts with playback, detection probability decreased as distance to a male’s territory increased, but remained constant as time since sunrise increased. Detection probability was greater when point counts included type 2 compared with type 1 song playback, particularly during the first 2 min of type 2 song playback. Golden-winged Warblers primarily use type 1 songs (often zee bee bee bee with a higher-pitched first note) in intersexual contexts and type 2 songs (strident, rapid stutter ending with a lower-pitched buzzy note) in intrasexual contexts. Distance to a male’s territory, ordinal date, and song playback type were associated with the type of behavioral response to song playback. Overall, ~2 min of type 2 song playback may increase the efficacy of point counts for monitoring populations of Golden-winged Warblers by increasing the conspicuousness of males for visual identification and offsetting the consequences of surveying later in the morning. Because playback may interfere with the ability to detect distant males, it is important to follow playback with a period of passive listening. Our results indicate that even in relatively open pasture vegetation, detection probability of male Golden-winged Warblers is imperfect and highly variable.
  • Trek to the Tidal Flats off Mononomy a “Must” for Birders | WCAI 081915
    Vern Laux: “Birders from all over the country and the world make the trip to visit Eastham and Chatham at this time of year for both the numbers and variety of shorebird species that can be seen. It is one of the best places; maybe the best place on the planet, to see the rare Hudsonian Godwit as it visits during its annual migration that takes it to the ends of the planet. This past week there were dozens of these godwits, as well as four Marbled Godwits, feeding on tidal flats at South Beach. | Hudsonian Godwits are relatively large, Arctic nesting shorebirds that visit here, feeding heavily, doubling their body weight in 2 or 3 weeks, before launching on a spectacular nonstop flight to northern South America. From there, they continue southward all the way to the bottom of that continent, spending the Austral summer on the flats around the Straits of Magellan in Patagonia in southern Argentina and Chile. | In fact all the Godwit species in the world, which are the Black-tailed Godwit, Bar-tailed Godwit, including both subspecies. Hudsonian Godwit and Marbled Godwit have all been seen in Chatham in the past as well. This malleable area is perhaps the best place in the world to see godwits. | For the next several weeks, the shorebird spectacle that is visible at these places is to my mind one of the wonders of the world. It is an awesome and humbling sight to see thousands of shorebirds, going on about their lives that are only stopping here briefly in their annual cycle of winging around a large part of the planet. That the birds know these food-rich areas are there and plan their annual migration to take advantage of them is a gift to us all.”
  • Minnesota angler: ‘Monster’ 45-pound lake trout was like pulling up a log – StarTribune.com 081915
    Nik Biebighauser of Minneapolis held the monster 45-pound lake trout he and his dad, Dave, caught in Lake Superior near Isle Royale National Park. They released the 47-inch fish,which would have been a state record had it been caught in Minnesota waters | So how big is a 45-pound lake trout? The Minnesota record lake trout is a 43-pound, 8-ounce fish caught near Hovland in 1955. (Length and girth are unknown.) | Isle Royale, though just 18 miles off Minnesota’s North Shore, is in Michigan waters. The Michigan state record lake trout is a 49-inch, 61½-pound behemoth caught in Lake Superior in 1997.
  • Isle Royale Queen IV runs aground – MiningGazette.com | News, Sports, Jobs – Houghton, Michigan – The Daily Mining Gazette 072915
    COPPER HARBOR – The Isle Royale Queen IV, operating out of Copper Harbor, ran aground Tuesday while on an evening cruise. U.S. Coast Guard was contacted by the Negaunee dispatch and told that the excursion vessel had run aground inside the harbor.
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