Variation in the Vocal Behavior of Common Loons

Common Loon photo by D. Poleschook

Mennill, D.  2014.  Variation in the Vocal Behavior of Common Loons (Gavia Immer):  Insights from Landscape-level Recordings.  Waterbirds 37 (Special Publication I): 26-36.

The song of the Common Loon (Gavia Immer) is one of the most evacuative of many areas of North America: spring would not be the same without this amazing song caring over northern lakes.  Using a custom-designed microphone array to collect landscape-scale recordings, Dan Mennill's bioacoustic analyses focused on understanding how their vocal output varied with time of day, time of year, and in response to variation in weather.  Common Loons showed significant diel variation in vocal output, producing more wail, yodel, and tremolo calls at night than during the day; the wail, yodel, and tremolo calls transmit significantly farther at night than during the day. These results provide quantitative details of Common Loon vocal signaling strategies, revealing that this species calls when abiotic conditions are ideal for long-range signaling. 

This article can be viewed at:  http://www.bioone.org/doi/full/10.1675/063.037.sp105

The 39th Annual Waterbird Society Meeting 11-15 Aug 2015

WATERBIRDS 2015: CHALLENGES AND RESPONSES

Call for Symposia and notice of Waterbird Society Meeting, Bar Harbor, ME, 11-15 Aug 2015. This is an invitation to anyone who would like to propose a Symposium for the 39th annual Waterbird Society meeting. The symposium can be for a full (approximately 14 presentations) or half day (7 presentations). Currently, we have two full-day symposia scheduled on American Oystercatcher Biology and on Double-crested Cormorant Biology and Management and one half-day symposium on Behaviour and Conservation. The meeting is being held in conjunction with the American Oystercatcher Working Group, the Wilson Plover Working Group and the Northwestern Atlantic Marine Bird Cooperative. Meeting information including details on the venue, field trips, accommodations and special events are now posted on the Waterbird Society web site. Registration information is also on the meeting web site. 

Please contact ERICA NOL or JOHN ANDERSON by 31 Jan 2015 if you have suggestions for further symposia topics. Abstract submission for contributed papers and posters will be available shortly on the meeting web site..

Migration: Idiosyncratic Migrations of Black Terns

Black Tern by Bob Gress

Idiosyncratic Migrations of Black Terns (Chlidonias niger): Diversity in Routes and Stopovers.  Jan van der Winden, Ruben C. Fijn, Peter W. van Horssen, Debby Gerritsen-Davidse and Theunis Piersma. 37(2):162-174. 2014

By 2013, six of 27 Black Terns (Chlidonias niger) from four Dutch colonies that had received light level geolocators in 2010–2011 had been recaptured. All six recovered individuals migrated to West Africa, but whereas one individual flew there nonstop, the others made stops of varying length en route. These included flights of 2,000–6,000 km between major stopovers, achieving travel speeds over 1,000 km/day.  This paper showed that Black Terns are long-distance migrants with substantial individual variation in migration patterns, including the use of staging sites, stopover times and travel distances. The variation in itineraries may imply that the distribution of the marine resources they rely on are relatively unpredictable. It remains to be seen whether the variability seen here reflects differences in otherwise fixed individual strategies or whether Black Terns are truly highly flexible.

The Importance of Survey Timing on Shorebird Density Estimates at East Bay, Nunavut, Canada

The Importance of Survey Timing on Shorebird Density Estimates at East Bay, Nunavut, Canada.  Melanie Dickie, Paul A. Smith and H. Grant Gilchrist.  Waterbirds 37(4): 394-401.  Waterbirds is an International journal, publishing new information on shorebirds and promoting new data on waterbirds from around the world.  In the December 2104 issue, this study examined the timing of breeding on counts of five shorebird species during transect surveys at East Bay, Nunavut, Canada, from 2000 to 2010. The species were: Black-bellied Plover (Pluvialis squatarola), Semipalmated Plover (Charadrius semipalmatus), Ruddy Turnstone (Arenaria interpres), White-rumped Sandpiper (Calidris fuscicollis) and Red Phalarope (Phalaropus fulicarius). Transect counts varied widely among species and years, and transect counts were most strongly predicted by the density of nests found during more intensive surveys. However, after accounting for this variation, survey counts were influenced substantially by survey timing. Surveys carried out shortly after the median date of nest initiation (∼2 days after) corresponded most closely to the densities of found nests, and if surveys were not within several days of the median date, the discrepancy between the two estimates was large. Although neither nest densities nor transect surveys are believed to be a perfect indication of local population status, these results suggest that the nearly inevitable variation in survey timing could introduce substantial bias into density estimates.