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Extreme endurance flights by landbirds crossing the Pacific Ocean: ecological corridor rather than barrier?

Gill RE, Tibbitts TL, Douglas DC, Handel CM, Mulcahy DM, Gottschalck JC, Warnock N, McCaffery BJ, Battley PF, Piersma T - Proc. Biol. Sci. (2009)

Bottom Line: Mountain ranges, deserts, ice fields and oceans generally act as barriers to the movement of land-dependent animals, often profoundly shaping migration routes.These extraordinary non-stop flights establish new extremes for avian flight performance, have profound implications for understanding the physiological capabilities of vertebrates and how birds navigate, and challenge current physiological paradigms on topics such as sleep, dehydration and phenotypic flexibility.We propose that this transoceanic route may function as an ecological corridor rather than a barrier, providing a wind-assisted passage relatively free of pathogens and predators.

View Article: PubMed Central - PubMed

Affiliation: USGS Alaska Science Center, 4210 University Drive, Anchorage, AK 99508, USA. robert_gill@usgs.gov

ABSTRACT
Mountain ranges, deserts, ice fields and oceans generally act as barriers to the movement of land-dependent animals, often profoundly shaping migration routes. We used satellite telemetry to track the southward flights of bar-tailed godwits (Limosa lapponica baueri), shorebirds whose breeding and non-breeding areas are separated by the vast central Pacific Ocean. Seven females with surgically implanted transmitters flew non-stop 8,117-11,680 km (10153+/-1043 s.d.) directly across the Pacific Ocean; two males with external transmitters flew non-stop along the same corridor for 7,008-7,390 km. Flight duration ranged from 6.0 to 9.4 days (7.8+/-1.3 s.d.) for birds with implants and 5.0 to 6.6 days for birds with externally attached transmitters. These extraordinary non-stop flights establish new extremes for avian flight performance, have profound implications for understanding the physiological capabilities of vertebrates and how birds navigate, and challenge current physiological paradigms on topics such as sleep, dehydration and phenotypic flexibility. Predicted changes in climatic systems may affect survival rates if weather conditions at their departure hub or along the migration corridor should change. We propose that this transoceanic route may function as an ecological corridor rather than a barrier, providing a wind-assisted passage relatively free of pathogens and predators.

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Southward flight tracks of nine bar-tailed godwits fitted with satellite transmitters (PTTs) during 2006 and 2007. Circles denote Argos locations collected during 6–8-hour intervals, and solid lines show interpolated 24–36-hour tracks between the PTT-reporting periods (see §2). Dotted lines are extensions of tracks between the last report of a PTT from a bird in flight and a confirmed sighting elsewhere of that bird. The dashed line represents the portion of flight following a confirmed stopover by a bird. Tracks are plotted on a Blue Marble image, geographic (Plate Carrée) projection (Stöckli et al. 2005). Inset shows individual track directions of nine PTT-tagged godwits departing on southward migration from Alaska (light blue circles) relative to directions towards which wind was blowing at 850 mb geopotential height (approx. 1500 m) during departures (orange circles). Arrows show mean direction of departing godwits (193°, light blue) and associated winds (174°, orange); length of arrows indicates strength of directionality (r=0.95, godwits; r=0.90, wind).
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fig1: Southward flight tracks of nine bar-tailed godwits fitted with satellite transmitters (PTTs) during 2006 and 2007. Circles denote Argos locations collected during 6–8-hour intervals, and solid lines show interpolated 24–36-hour tracks between the PTT-reporting periods (see §2). Dotted lines are extensions of tracks between the last report of a PTT from a bird in flight and a confirmed sighting elsewhere of that bird. The dashed line represents the portion of flight following a confirmed stopover by a bird. Tracks are plotted on a Blue Marble image, geographic (Plate Carrée) projection (Stöckli et al. 2005). Inset shows individual track directions of nine PTT-tagged godwits departing on southward migration from Alaska (light blue circles) relative to directions towards which wind was blowing at 850 mb geopotential height (approx. 1500 m) during departures (orange circles). Arrows show mean direction of departing godwits (193°, light blue) and associated winds (174°, orange); length of arrows indicates strength of directionality (r=0.95, godwits; r=0.90, wind).

Mentions: Nine satellite-tagged bar-tailed godwits departed Alaska between 30 August and 7 October with their initial tracks strongly concentrated (r=0.95, Z=8.19, p<0.001) in a southerly direction (193°; figure 1). The birds continued on this general heading across the entire central Pacific Ocean along a relatively narrow corridor (less than 1800 km wide, 10–15% of the width of the Pacific between the tropics of Cancer and Capricorn). Tracking distances from each bird's last reported location in Alaska to its first known landfall (or last reported location) ranged from 8117 to 11 680 km (10 153±1043 s.d.) for seven females with surgically implanted PTTs, and from 7008 to 7390 km for the two males with externally attached PTTs (table 1). Duration of these flights ranged from 6.0 to 9.4 days (7.8±1.3 s.d.) for birds with implants and from 5.0 to 6.6 days for birds with externally attached PTTs.


Extreme endurance flights by landbirds crossing the Pacific Ocean: ecological corridor rather than barrier?

Gill RE, Tibbitts TL, Douglas DC, Handel CM, Mulcahy DM, Gottschalck JC, Warnock N, McCaffery BJ, Battley PF, Piersma T - Proc. Biol. Sci. (2009)

Southward flight tracks of nine bar-tailed godwits fitted with satellite transmitters (PTTs) during 2006 and 2007. Circles denote Argos locations collected during 6–8-hour intervals, and solid lines show interpolated 24–36-hour tracks between the PTT-reporting periods (see §2). Dotted lines are extensions of tracks between the last report of a PTT from a bird in flight and a confirmed sighting elsewhere of that bird. The dashed line represents the portion of flight following a confirmed stopover by a bird. Tracks are plotted on a Blue Marble image, geographic (Plate Carrée) projection (Stöckli et al. 2005). Inset shows individual track directions of nine PTT-tagged godwits departing on southward migration from Alaska (light blue circles) relative to directions towards which wind was blowing at 850 mb geopotential height (approx. 1500 m) during departures (orange circles). Arrows show mean direction of departing godwits (193°, light blue) and associated winds (174°, orange); length of arrows indicates strength of directionality (r=0.95, godwits; r=0.90, wind).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2664343&req=5

fig1: Southward flight tracks of nine bar-tailed godwits fitted with satellite transmitters (PTTs) during 2006 and 2007. Circles denote Argos locations collected during 6–8-hour intervals, and solid lines show interpolated 24–36-hour tracks between the PTT-reporting periods (see §2). Dotted lines are extensions of tracks between the last report of a PTT from a bird in flight and a confirmed sighting elsewhere of that bird. The dashed line represents the portion of flight following a confirmed stopover by a bird. Tracks are plotted on a Blue Marble image, geographic (Plate Carrée) projection (Stöckli et al. 2005). Inset shows individual track directions of nine PTT-tagged godwits departing on southward migration from Alaska (light blue circles) relative to directions towards which wind was blowing at 850 mb geopotential height (approx. 1500 m) during departures (orange circles). Arrows show mean direction of departing godwits (193°, light blue) and associated winds (174°, orange); length of arrows indicates strength of directionality (r=0.95, godwits; r=0.90, wind).
Mentions: Nine satellite-tagged bar-tailed godwits departed Alaska between 30 August and 7 October with their initial tracks strongly concentrated (r=0.95, Z=8.19, p<0.001) in a southerly direction (193°; figure 1). The birds continued on this general heading across the entire central Pacific Ocean along a relatively narrow corridor (less than 1800 km wide, 10–15% of the width of the Pacific between the tropics of Cancer and Capricorn). Tracking distances from each bird's last reported location in Alaska to its first known landfall (or last reported location) ranged from 8117 to 11 680 km (10 153±1043 s.d.) for seven females with surgically implanted PTTs, and from 7008 to 7390 km for the two males with externally attached PTTs (table 1). Duration of these flights ranged from 6.0 to 9.4 days (7.8±1.3 s.d.) for birds with implants and from 5.0 to 6.6 days for birds with externally attached PTTs.

Bottom Line: Mountain ranges, deserts, ice fields and oceans generally act as barriers to the movement of land-dependent animals, often profoundly shaping migration routes.These extraordinary non-stop flights establish new extremes for avian flight performance, have profound implications for understanding the physiological capabilities of vertebrates and how birds navigate, and challenge current physiological paradigms on topics such as sleep, dehydration and phenotypic flexibility.We propose that this transoceanic route may function as an ecological corridor rather than a barrier, providing a wind-assisted passage relatively free of pathogens and predators.

View Article: PubMed Central - PubMed

Affiliation: USGS Alaska Science Center, 4210 University Drive, Anchorage, AK 99508, USA. robert_gill@usgs.gov

ABSTRACT
Mountain ranges, deserts, ice fields and oceans generally act as barriers to the movement of land-dependent animals, often profoundly shaping migration routes. We used satellite telemetry to track the southward flights of bar-tailed godwits (Limosa lapponica baueri), shorebirds whose breeding and non-breeding areas are separated by the vast central Pacific Ocean. Seven females with surgically implanted transmitters flew non-stop 8,117-11,680 km (10153+/-1043 s.d.) directly across the Pacific Ocean; two males with external transmitters flew non-stop along the same corridor for 7,008-7,390 km. Flight duration ranged from 6.0 to 9.4 days (7.8+/-1.3 s.d.) for birds with implants and 5.0 to 6.6 days for birds with externally attached transmitters. These extraordinary non-stop flights establish new extremes for avian flight performance, have profound implications for understanding the physiological capabilities of vertebrates and how birds navigate, and challenge current physiological paradigms on topics such as sleep, dehydration and phenotypic flexibility. Predicted changes in climatic systems may affect survival rates if weather conditions at their departure hub or along the migration corridor should change. We propose that this transoceanic route may function as an ecological corridor rather than a barrier, providing a wind-assisted passage relatively free of pathogens and predators.

Show MeSH
Related in: MedlinePlus