Evidence for a navigational map stretching across the continental U.S. in a migratory songbird - PubMed (original) (raw)

Evidence for a navigational map stretching across the continental U.S. in a migratory songbird

Kasper Thorup et al. Proc Natl Acad Sci U S A. 2007.

Abstract

Billions of songbirds migrate several thousand kilometers from breeding to wintering grounds and are challenged with crossing ecological barriers and facing displacement by winds along the route. A satisfactory explanation of long-distance animal navigation is still lacking, partly because of limitations on field-based study. The navigational tasks faced by adults and juveniles differ fundamentally, because only adults migrate toward wintering grounds known from the previous year. Here, we show by radio tracking from small aircraft that only adult, and not juvenile, long-distance migrating white-crowned sparrows rapidly recognize and correct for a continent-wide displacement of 3,700 km from the west coast of North America to previously unvisited areas on the east coast. These results show that the learned navigational map used by adult long-distance migratory songbirds extends at least on a continental scale. The juveniles with less experience rely on their innate program to find their distant wintering areas and continue to migrate in the innate direction without correcting for displacement.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Fig. 1.

Fig. 1.

The displacement of white-crowned sparrows, Zonotrichia leucophrys gambelii, from Sunnyside, WA, to Princeton, NJ. Possible migration routes after release at Princeton are shown as normal migration direction (1), toward wintering area (2), and back toward capture site (3). Breeding area (green), wintering area (cyan), and normal migration route (blue) are indicated.

Fig. 2.

Fig. 2.

Tracks of adult (blue) and juvenile (red) birds released at Princeton after displacement from Sunnyside, WA. Adults and juveniles were released at sites 7.3 km apart. Images were created by using Google Earth mapping service.

Fig. 3.

Fig. 3.

Direction from the release site to the last observed position. Only positions >25 km from the release site are included. Adults are shown in blue, and juveniles are shown in red. For adults, the mean vector is α = 252 ± 18° and r = 0.931 (Z = 6.94, n = 8, P < 0.001, Rayleigh test), and for juveniles, it is α = 192 ± 6° and r = 0.99 (Z = 8.82, n = 9, P < 0.001, Rayleigh test). Mean directions and 95% confidence intervals are shown for each group, respectively. The single adult with a southerly orientation probably drifted initially in strong northwesterly winds.

Fig. 4.

Fig. 4.

Direction from release site to the first observed position >5 km from the release site. Adults are shown in blue, and juveniles are shown in red. For adults, the mean vector is α = 221 ± 25° and r = 0.698 (Z = 7.31, n = 15, P < 0.001, Rayleigh test), and for juveniles, it is α = 135 ± 29° and r = 0.631 (Z = 5.96, n = 15, P = 0.002, Rayleigh test). Mean directions and 95% confidence intervals are shown for each group, respectively.

Similar articles

Cited by

References

    1. Sutherland WJ. Nature. 1988;334:471–472.
    1. Alerstam T. Science. 2006;291:300–303. - PubMed
    1. Berthold P. Bird Migration: A General Survey. New York: Oxford Univ Press; 2001.
    1. Wallraff HG. In: Orientation in Birds. Berthold P, editor. Basel: Birkhäuser; 1991. pp. 128–165.
    1. Larkin RP. In: Avian Navigation. Papi F, Wallraff HG, editors. Berlin: Springer; 1982. pp. 28–37.

Publication types

MeSH terms

LinkOut - more resources