Research ArticleETHOLOGY

Costs of migratory decisions: A comparison across eight white stork populations

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Science Advances  22 Jan 2016:
Vol. 2, no. 1, e1500931
DOI: 10.1126/sciadv.1500931
  • Fig. 1 Migratory behavior of juveniles from eight different populations.

    (A) Migration paths of 62 individuals tracked with GPS/GSM (Global System for Mobile Communications) (eight individuals died before migrating). Maps depicted are OpenStreetMap images (www.openstreetmap.org/copyright; https://creativecommons.org/licenses/by-sa/2.0/) accessed through the R package OpenStreetMap. (B) Departure date of the studied populations. Color scale indicates departure dates (white indicating no departure). (C) Departure date as a function of maximum distance reached (each color represents one population). Dots in the light gray–shaded area represent individuals that left their natal grounds but survived for less than 150 days. SW, southwest.

  • Fig. 2 Activity measures of juvenile white storks.

    (A) Summed activity (ODBA) of the first 5 months of a juvenile’s life as a function of total distance flown during the same time. The solid gray line represents the third-order polynomial regression. The best-fitting regression is provided by the equation Y = 387.2 + 1.344 × 10−11 X3. (B) Average activity (ODBA) of a migration day in relation to average activity of a stopover day. Color represents the different populations. Gray dashed line is a reference line.

  • Fig. 3 Activity and thermal uplift.

    Activity (sum of daily ODBA values) as a function of thermal uplift (mean of daily thermal uplift), during flight days, depending on the location of the bird (B). Blue and light brown correspond to Europe/Middle East (north of 33°N) and Africa (south of 33°N), respectively. Plots on the top (A) and the side (C) are the density histograms of thermal uplift (top) and ODBA (right).

  • Fig. 4 Activity in relation to human population density and vegetation cover.

    Daily activity (sum of hourly ODBA averages) as a function of human population density (mean of the day) (B) and vegetation cover of shrubs and low-lying bushes [“low vegetation cover,” European Centre for Medium-Range Weather Forecasts (ECMWF), mean of the day] (D). Blue and light brown correspond to birds that overwintered north and south of 33°N, respectively. Plots on the top and the side are the density histograms of population density (A), vegetation cover (C), and ODBA (E).

  • Table 1 Locations and sample sizes of the different study populations.

    Central GPS location of study sites; number of birds tagged (in parenthesis: number of birds with high-resolution data, that is, GPS and acceleration data taken every 5 min); number of birds still alive after 5 and 12 months (in parenthesis: percentage of total number tagged).

    PopulationCentral GPS coordinates
    of study site
    No. of birds
    LongitudeLatitudeTagged (high resolution)Alive after 5 monthsAlive after 12 months
    Armenia44°31′1.2″40°12′0″8 (1)2 (25%)2 (25%)
    Greece26°10′4.8″40°53′27.6″10 (1)5 (50%)2 (20%)
    Poland15°30′7.2″51°56′13.2″4 (2)2 (50%)2 (50%)
    Russia37°23′31.2″55°38′49.2″10 (4)7 (70%)4 (40%)
    Spain−6°1′33.6″37°21′25.2″11 (1)3 (27%)1 (9%)
    Southwest Germany8°56′2.4″47° 45′ 10.8″12 (5)6 (46%)5 (38%)
    Tunisia10°15′39.6″36° 48′ 32.4″9 (2)4 (44%)2 (22%)
    Uzbekistan69°2′16.8″40° 59′ 45.6″6 (3)4 (67%)3 (50%)
    TOTAL70 (19)33 (47%)21 (30%)

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/2/1/e1500931/DC1

    Table S1. Results of linear regression models concerning the effects of population on departure date.

    Table S2. Results of linear regression models concerning the effects of population on maximum distance reached.

    Table S3. GLMM model results for animal activity (ODBA) showing the effects of the main predictors. North of 33°N was incorporated in the intercept.

    Table S4. GLMM model results concerning the effect of daily distance moved on the location of the wintering grounds.

    Table S5. GLMM model results for animal activity (ODBA) showing the effects of human population density (log) and vegetation cover (centered).

  • Supplementary Materials

    This PDF file includes:

    • Table S1. Results of linear regression models concerning the effects of population on departure date.
    • Table S2. Results of linear regression models concerning the effects of population on maximum distance reached.
    • Table S3. GLMM model results for animal activity (ODBA) showing the effects of the main predictors. North of 33°N was incorporated in the intercept.
    • Table S4. GLMM model results concerning the effect of daily distance moved on the location of the wintering grounds.
    • Table S5. GLMM model results for animal activity (ODBA) showing the effects of human population density (log) and vegetation cover (centered).

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