Occurrence of quiescence in free-ranging migratory songbirds

Schofield, Lynn N.; Deppe, Jill L.; Diehl, Robert H.; Ward, Michael P.; Bolus, Rachel T.; Zenzal, Theodore J.; Smolinsky, Jaclyn A.; Moore, Frank R.

doi:10.1007/s00265-018-2449-y

Cited by 13 publications

(14 citation statements)

References 47 publications

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“…Each transmitter had a unique frequency between 163.828 and 166.060 MHz, had pulse width (i.e. the duration of the radio pulse) of either 22 + 2 or 28+ 2 ms (+s.e., manufacturer specified) and a pulse interval of 350 + 10 ms. We attached transmitters to birds dorsally between the wings with an eyelash adhesive (Revlon w brand) and a small amount of cyanoacrylate glue (Loctite w brand) [40]. Transmitters weighed 1.1 g with cloth and thread, and had a lifespan of approximately 28 days.…”

Section: Materials and Methods (A) Study Speciesmentioning

confidence: 99%

Estimating apparent survival of songbirds crossing the Gulf of Mexico during autumn migration

et al. 2018

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Many migratory bird species are declining, and the migratory period may limit populations because of the risk in traversing large geographical features during passage. Using automated radio-telemetry, we tracked 139 Swainson's thrushes ( Catharus ustulatus ) departing coastal Alabama, USA and crossing the Gulf of Mexico to arrive in the Yucatan Peninsula, Mexico during autumn. We estimated apparent survival and examined how extrinsic (weather variables and day of year) and intrinsic (fat load, sex and age) factors influenced survival using a mark-recapture approach. We also examined how favourability of winds for crossing the Gulf varied over the past 25 years. Fat load, day of year and wind profit were important factors in predicting which individuals survived crossing the Gulf. Survival estimates varied with wind profit and fat, but generally, fat birds departing on days with favourable wind profits had an apparent survival probability of greater than 0.90, while lean individuals with no or negative wind profits had less than 0.33. The proportion of favourable nights varied within and among years, but has increased over the last 25 years. While conservation strategies cannot improve extrinsic factors, they can provide opportunities for birds to refuel before crossing large geographical features through protecting and creating high-quality stopover sites.

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Section: Materials and Methods (A) Study Speciesmentioning

confidence: 99%

Estimating apparent survival of songbirds crossing the Gulf of Mexico during autumn migration

et al. 2018

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“…Some of the variation in the activity transition times could be attributed to species, sex, age and year, but no comparisons were made between departure and non-departure days. In another study, Schofield et al (2018) observed differences among species in the amount of locomotor activity (versus quiescence) in a defined two-hour period prior to migratory departure. Evening activity was not compared between departure and pre-departure days, nor was the precise onset of quiescence determined.…”

Section: Introductionmentioning

confidence: 98%

“…Between migratory flights, individuals undertake a sequence of activities: physiological recovery from the previous flight, periods of refueling and overnight resting, and finally, departure for the next migratory flight, which usually happens after sunset (Schmaljohann et al 2011, Schmaljohann and Eikenaar 2017). On their departure day, the usual routine is that birds cease diurnal activity at around sunset, arouse from rest later in the night, and then quickly depart on their flights (Zúñiga et al 2016, Schofield et al 2018). However, there can be deviations including the inclusion of short‐duration exploratory flights (Schmaljohann et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Evening locomotor activity during stopover differs on pre‐departure and departure days in free‐living songbirds

Morbey

Beauchamp

Bonner

et al. 2020

Journal of Avian Biology

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The length of time songbirds remain at a migratory stopover site is likely regulated by a daily stay/go decision informed by fat stores and weather conditions, but the finerscale timing of this decision and associated pre-departure behaviours are still poorly understood. Using automated radiotelemetry of free-living songbirds captured at a migratory stopover site in spring, we tested whether individuals change their locomotor activity near sunset on their migratory departure day compared to their non-departure days. To do so, we extracted precise transition times between diurnal activity and nocturnal inactivity, which always precedes departure, using changepoint analysis of radio transmission signal strength. Among four warbler species, individuals extended diurnal activity by 8-19 min towards sunset on their departure day. In three species, this extension was significant. In contrast, white-throated sparrows significantly shortened diurnal activity on their departure day by 13 min, also towards sunset. This is the first study to detect and quantify a change in locomotor activity schedule on departure versus non-departure days in free-living songbirds, and is consistent with the hypothesis that birds engage in pre-departure preparatory behaviours near sunset.

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“…Field-based studies conducted at the individual level are particularly useful for understanding such responses to environmental cues and for linking physiology and behavior. Automated radio-telemetry is increasingly being used as a tool to quantify the behavior of songbirds due to its ability to track and monitor activity of organisms with relatively high temporal and spatial precision at local to broad spatial scales (Goymann et al 2010, Bridge et al 2011, Ward et al 2014, Brown and Taylor 2015, Taylor et al 2017, Schofield et al 2018). However, a major uncertainty in the application of automated radio-telemetry is the effective detection range of receiving antennas, especially in natural habitats with myriad factors potentially interfering with signal transmission .…”

Section: Introductionmentioning

confidence: 99%

“…, Schofield et al. ). However, a major uncertainty in the application of automated radio‐telemetry is the effective detection range of receiving antennas, especially in natural habitats with myriad factors potentially interfering with signal transmission (Kays et al.…”

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Detection range of songbirds using a stopover site by automated radio‐telemetry

et al. 2019

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A major uncertainty in automated radio‐telemetry studies of small birds is the detection range of receiving antennas. We compared simultaneous daytime detections (± 30 s) by automated and manual radio‐telemetry to assess detection probability and the proportion of transmissions detected for birds on migratory stopover as a function of distance, foraging guild (Black‐throated Blue Warblers, Setophaga caerulescens, and Yellow‐rumped Warblers, Dendroica coronata coronata, represented mid‐canopy foliage gleaners and White‐throated Sparrows, Zonotrichia albicollis, represented a ground forager), habitat type, meteorological variables, tower antenna number (1–4), and the position of a bird relative to the receiving antenna's bearing (offset angle). Our study was conducted at a migratory stopover site in southern Ontario, Canada. Most detections were in dense to sparse forest, and all individuals were within 1.03 km of the automated receiving station. Daily detection probability was near 100% for both foraging guilds. However, within 30 s before and after a manual radio‐telemetry location was made, detection probability and the proportion of transmissions detected by automated radio‐telemetry declined with distance, was higher for warblers than sparrows, and was lowest for 90° offset angles. Our results suggest that when research goals do not require detections with high temporal frequency, e.g., estimation of departure date or daily departure probability, our study design had an effective detection range of at least 1 km. However, where temporal precision is required, e.g., to investigate movements and changes in activity levels during stopover, detection range was ~300 m for ground‐foraging sparrows and 600 m for mid‐canopy foraging warblers, which is much lower than the presumed detection range of antennas under optimal conditions (15 km). This corresponds to a spatial area of coverage for forest‐dwelling birds of ~0.3–1.1 km2. Our results suggest that to optimally configure an automated radio‐telemetry array at the regional scale, investigators should carefully consider detection range and its underlying covariates, including species type, the habitat matrix, and the orientation of antennas relative to preferred habitat.

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Occurrence of quiescence in free-ranging migratory songbirds

Cited by 13 publications

References 47 publications

Estimating apparent survival of songbirds crossing the Gulf of Mexico during autumn migration

Estimating apparent survival of songbirds crossing the Gulf of Mexico during autumn migration

Evening locomotor activity during stopover differs on pre‐departure and departure days in free‐living songbirds

Detection range of songbirds using a stopover site by automated radio‐telemetry

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