Revealing migratory path, important stopovers and non-breeding areas of a boreal songbird in steep decline

2021 ◽  
Vol 8 (1) ◽  
pp. 168-191
Author(s):  
Julie C. Hagelin ◽  
Michael T. Hallworth ◽  
Christopher P. Barger ◽  
James A. Johnson ◽  
Kristin A. DuBour ◽  
...  
Keyword(s):  
Light Level ◽  
Migration Speed ◽  
Aerial Insectivore ◽  
Migratory Routes ◽  
Migratory Path ◽  
Steep Decline ◽  
Migratory Timing ◽  
Migratory Period ◽  
Travel Distances ◽  
Total Migration

Abstract The Olive-sided Flycatcher (Contopus cooperi) is a steeply declining aerial insectivore with one of the longest migrations of any North American passerine. We deployed light-level geolocators and archival GPS tags on breeders in boreal Alaska to determine migratory routes, important stopovers and non-breeding locations. Data from 16 individuals revealed a median 23,555 km annual journey (range: 19,387, 27,292 km) over 95 days (range: 83, 139 days) with wintering occurring in three regions of South America (NW Colombia/Ecuador, central Peru and W Brazil/S Peru). We developed a new method to identify “Important Stopovers” by quantifying intensity of use (a function of bird numbers and stop durations) along migratory routes. We identified 13 Important Stopovers that accounted for ~66% of the annual migratory period, suggestive of refueling activities. Some sites coincided with key areas previously identified for other Neotropical-Nearctic migrants. Percent land “protected” at Important Stopovers, as defined by IUCN, ranged from 3.8% to 49.3% (mean [95% CI]: 17.3% [9.6, 25.0]). Total migration speed did not differ by season (median: 255 km day-1, range: 182, 295km day-1), despite greater spring travel distances. Birds with longer non-breeding periods, however, migrated north faster. Climate-driven mismatches in migratory timing may be less of a concern for western than for eastern flycatcher populations, given recent con-generic analyses (C. sordidulus, C. virens). However, accelerated high-latitude changes, may nonetheless impact boreal breeders.

Nonbreeding season movements of a migratory songbird are related to declines in resource availability

The Auk ◽  
2019 ◽  
Vol 136 (3) ◽  
Author(s):  
Samantha M Knight ◽  
Elizabeth A Gow ◽  
David W Bradley ◽  
Robert G Clark ◽  
Marc Bélisle ◽  
...  
Keyword(s):  
Resource Availability ◽  
Large Scale ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Light Level ◽  
Tree Swallow ◽  
Breeding Sites ◽  
Nonbreeding Season ◽  
Aerial Insectivore ◽  
Migratory Songbird

Abstract There have been an increasing number of observations of itinerancy in migratory songbirds, where individuals move among 2 or more widely separated areas during the “stationary” nonbreeding season. Knowledge of such movements and an understanding of what drives them are important for predicting how migratory populations will respond to environmental change. In this study, we investigated nonbreeding movements of the Tree Swallow (Tachycineta bicolor), an aerial insectivore that breeds across North America and spends the nonbreeding season around the Gulf of Mexico, Florida, Mexico, Central America, and the Caribbean. With year-round tracking data obtained from 133 light-level geolocators deployed at 12 breeding sites ranging from Alaska to Nova Scotia to North Carolina, we show that 44% of individuals made at least one large-scale movement (range: 301–1,744 km) within the nonbreeding range. The frequency of itinerancy decreased with longitude, such that 75% of individuals made a movement in the western portion of the nonbreeding range compared to only 31% in the east. Using the Normalized Difference Vegetation Index (NDVI) as a proxy for resource availability, we found that when individuals did move, they were more likely to move from sites where resources were deteriorating faster (a more negative change in NDVI prior to departure) than their destination sites. There was also evidence that individuals moved to destination sites with higher NDVI and temperature in the autumn, but not in the winter. Our results suggest movements of Tree Swallows during the nonbreeding season are influenced by resource availability, but because not all individuals used multiple nonbreeding sites, the density of individuals at a site and the level of competition may have also been a factor influencing nonbreeding season movements.

scholarly journals Concentration of a widespread breeding population in a few critically important nonbreeding areas: Migratory connectivity in the Prothonotary Warbler

The Condor ◽  
2019 ◽  
Vol 121 (2) ◽  
Author(s):  
Christopher M Tonra ◽  
Michael T Hallworth ◽  
Than J Boves ◽  
Jessie Reese ◽  
Lesley P Bulluck ◽  
...  
Keyword(s):  
Annual Cycle ◽  
Large Scale ◽  
Light Level ◽  
Breeding Population ◽  
Migratory Bird ◽  
Migratory Connectivity ◽  
Long Distance ◽  
Breeding Range ◽  
Migratory Routes ◽  
Prothonotary Warbler

Abstract One of the greatest challenges to informed conservation of migratory animals is elucidating spatiotemporal variation in distributions. Without such information, it is impossible to understand full-annual-cycle ecology and effectively implement conservation actions that address where and when populations are most limited. We deployed and recovered light-level geolocators (n = 34) at 6 breeding sites in North America across the breeding range of a declining long-distance migratory bird, the Prothonotary Warbler (Protonotaria citrea). We sought to determine migratory routes, stopover location and duration, and the location of overwintering grounds. We found that the species exhibits a large-scale, east‒west split in migratory routes and weak migratory connectivity across its range. Specifically, almost all individuals, regardless of breeding origin, overlapped in their estimated wintering location in northern Colombia, in an area 20% the size of the breeding range. Additionally, most of the individuals across all breeding locations concentrated in well-defined stopover locations in Central America while en route to Colombia. Although error inherent in light-level geolocation cannot be fully ruled out, surprisingly much of the estimated wintering area included inland areas even though the Prothonotary Warbler is considered a specialist on coastal mangroves in winter. Based on these results, conservation efforts directed at very specific nonbreeding geographical areas will potentially have benefits across most of the breeding population. Our findings highlight the importance of using modern technologies to validate assumptions about little-studied portions of a species’ annual cycle, and the need to distribute sampling across its range.

scholarly journals Migratory connectivity of Golden-crowned Sparrows from two wintering regions in California

2016 ◽  
Vol 3 (1) ◽  
pp. 48-56 ◽  
Author(s):  
Renée L Cormier ◽  
Diana L Humple ◽  
Thomas Gardali ◽  
Nathaniel E Seavy
Keyword(s):  
Gulf Coast ◽  
Light Level ◽  
Migration Route ◽  
Migratory Connectivity ◽  
Migration Routes ◽  
Breeding Sites ◽  
Wintering Birds ◽  
Migratory Routes ◽  
Coastal Birds ◽  
And Control

AbstractKnowledge of migratory connectivity is critical to understanding the consequences of habitat loss and climate change on migratory species. We used light-level geolocators to determine breeding locations and migratory routes of wintering Golden-crowned Sparrows (Zonotrichia atricapilla) in two regions of California, USA. Eight out of 9 birds tagged at coastal-wintering sites in Marin County went to breeding sites along the Gulf Coast of Alaska, while 7 out of 8 inland-wintering birds in Placer County migrated to interior sites in the Yukon, Northwest Territories, and British Columbia, Canada. Our estimate of the strength of migratory connectivity was relatively high (rm = 0.66). Coastal-wintering birds followed a coastal migration route while inland-wintering birds migrated inland. Coastalwintering birds migrated significantly farther than inland birds (3,624 km versus 2,442 km). Coastal birds traveled at a greater rate during spring migration (179 km/d) than did inland birds (118 km/d), but there was no statistical difference in the rate of fall migration (167 km/d and 111 km/d, respectively). Dates of arrival and departure, and duration of spring and fall migration, did not differ between groups, nor did return rates. Rates of return also did not differ between tagged and control birds. The distinct migration routes and breeding areas suggests that there may be more structuring in the migratory geography of the Golden-crowned Sparrow than in a simple panmictic population.

scholarly journals Dramatic intraspecific differences in migratory routes, stopover sites and wintering areas, revealed using light-level geolocators

2012 ◽  
Vol 279 (1747) ◽  
pp. 4582-4589 ◽  
Author(s):  
Kira E. Delmore ◽  
James W. Fox ◽  
Darren E. Irwin
Keyword(s):  
North America ◽  
Light Level ◽  
Conservation Strategies ◽  
Breeding Ecology ◽  
Catharus Ustulatus ◽  
Mitochondrial Haplotypes ◽  
Breeding Populations ◽  
Migratory Routes ◽  
Loop Migration ◽  
Using Data

Migratory divides are contact zones between breeding populations that use divergent migratory routes and have been described in a variety of species. These divides are of major importance to evolution, ecology and conservation but have been identified using limited band recovery data and/or indirect methods. Data from band recoveries and mitochondrial haplotypes suggested that inland and coastal Swainson's thrushes ( Catharus ustulatus ) form a migratory divide in western North America. We attached light-level geolocators to birds at the edges of this contact zone to provide, to our knowledge, the first direct test of a putative divide using data from individual birds over the entire annual cycle. Coastal thrushes migrated along the west coast to Mexico, Guatemala and Honduras. Some of these birds used multiple wintering sites. Inland thrushes migrated across the Rocky Mountains, through central North America to Columbia and Venezuela. These birds migrated longer distances than coastal birds and performed a loop migration, navigating over the Gulf of Mexico in autumn and around this barrier in spring. These findings support the suggestion that divergent migratory behaviour could contribute to reproductive isolation between migrants, advance our understanding of their non-breeding ecology, and are integral to development of detailed conservation strategies for this group.

Software pattern recognition applied to nanodiffraction patterns from a STEM instrument

1986 ◽  
Vol 44 ◽  
pp. 694-695
Author(s):  
G.Y. Fan ◽  
J.M. Cowley
Keyword(s):  
Image Processing ◽  
Pattern Recognition ◽  
Computer Software ◽  
Processing System ◽  
Light Level ◽  
Host Computer ◽  
Low Light ◽  
Image Processing System ◽  
Recent Developments ◽  
On Line

In recent developments, the ASU HB5 has been modified so that the timing, positioning, and scanning of the finely focused electron probe can be entirely controlled by a host computer. This made the asynchronized handshake possible between the HB5 STEM and the image processing system which consists of host computer (PDP 11/34), DeAnza image processor (IP 5000) which is interfaced with a low-light level TV camera, array processor (AP 400) and various peripheral devices. This greatly facilitates the pattern recognition technique initiated by Monosmith and Cowley. Software called NANHB5 is under development which, instead of employing a set of photo-diodes to detect strong spots on a TV screen, uses various software techniques including on-line fast Fourier transform (FFT) to recognize patterns of greater complexity, taking advantage of the sophistication of our image processing system and the flexibility of computer software.

Low-light-level three-dimensional video microscope with long working distance objective lenses

1994 ◽  
Vol 52 ◽  
pp. 226-227
Author(s):  
W. Lin ◽  
J. Gregorio ◽  
T.J. Holmes ◽  
D. H. Szarowski ◽  
J.N. Turner
Keyword(s):  
Three Dimensional ◽  
Light Level ◽  
Stereo Pair ◽  
Light Illumination ◽  
Initial Image ◽  
Low Light ◽  
Image Recording ◽  
Depth Discrimination ◽  
Video Microscope ◽  
Working Distance

A low-light level video microscope with long working distance objective lenses has been built as part of our integrated three-dimensional (3-D) light microscopy workstation (Fig. 1). It allows the observation of living specimens under sufficiently low light illumination that no significant photobleaching or alternation of specimen physiology is produced. The improved image quality, depth discrimination and 3-D reconstruction provides a versatile intermediate resolution system that replaces the commonly used dissection microscope for initial image recording and positioning of microelectrodes for neurobiology. A 3-D image is displayed on-line to guide the execution of complex experiments. An image composed of 40 optical sections requires 7 minutes to process and display a stereo pair.The low-light level video microscope utilizes long working distance objective lenses from Mitutoyo (10X, 0.28NA, 37 mm working distance; 20X, 0.42NA, 20 mm working distance; 50X, 0.42NA, 20 mm working distance). They provide enough working distance to allow the placement of microelectrodes in the specimen.

Flow velocity and light level drive non-linear response of seagrass Zostera noltei to ammonium enrichment

2016 ◽  
Vol 545 ◽  
pp. 109-121 ◽  
Author(s):  
B Villazán ◽  
FG Brun ◽  
V González‑Ortiz ◽  
F Moreno‑Marín ◽  
TJ Bouma ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Linear Response ◽  
Light Level ◽  
Zostera Noltei ◽  
Non Linear

Dammed If You Don’t, But What If You Do? Breaching the Lower Snake River Dams in Washington State

2020 ◽  
Vol 4 (1) ◽  
pp. 1-12
Author(s):  
Elizabeth C. Lopardo ◽  
Clare M. Ryan
Keyword(s):  
Policy Process ◽  
Food Source ◽  
Washington State ◽  
Federal Agencies ◽  
Snake River ◽  
Environmental Groups ◽  
Steep Decline ◽  
Mitigation Techniques ◽  
Economic Analyses

Four dams on the lower Snake River in Washington State generate hydropower and allow for regional agriculture and barge shipping to Portland OR. However, the dams impede the migration of local salmon populations (Oncorhynchus spp.), which are in steep decline, and drastically impact the populations of salmon and orca whales, for whom salmon are a primary food source. For years, environmental groups have argued for breaching the dams; other interests counter that the dams are too critical to the economy of the region to lose; and federal agencies assert that the dams can remain and salmon populations will recover with mitigation techniques. Scientific and economic analyses, litigation, and elected officials’ efforts have not been able to move the issue towards a solution. Readers will examine the interests of primary actors in the issue, how they influence the policy process, the role of scientific and economic analyses, and possible approaches for resolving the issue.

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