Factors affecting breeding ground return rates of all banded Hudsonian godwits, 2010–2011.

<p>Parameter estimates for a mixed-effect logistic regression model predicting breeding ground return rates of individual godwits carrying alpha-alpha flags and data loggers. (<i>n</i> = 74).</p

Map showing the migration routes of Hudsonian godwits breeding at Beluga River, Alaska.

<p>Twenty-six individuals were tracked across three years 2009–2012, though for ease of presentation this map only shows those from 2009–2010 (<i>n</i> = 12), using British Antarctic Survey Mk-14 geolocation-tracking devices. Each red triangle denotes the location of an individual on one day, but does not necessarily indicate that the individual stopped in that location. Each blue circle denotes a region in which the majority of godwits stopped and congregated in both years. From north to south, those regions are: Beluga River, Alaska (nesting site); central Saskatchewan (staging site southward migration); Rainwater Basin, Nebraska (staging site northward migration); Amazon Basin, Colómbia (stopover site southward migration); Buenos Aires Province, Argentina (stopover site southward migration); and Isla Chiloé, Chile (nonbreeding site). Note that the typical annual migratory route is a clock-wise loop.</p

Travel rate for migrating swifts in relation to latitude.

<p>Daily travel rate in relation to latitude calculated for 3-day segments for six migrating swifts for periods of actual travel during (A) autumn and (B) spring migration, respectively. The curves show second degree polynomial fitted to the data: (A) U_trav = 155.5+15.6 Lat –0.29 Lat², with maximum travel rate at latitude 27.1°N; (B) U_trav = 278.4+19.3 Lat –0.39 Lat², with maximum travel rate at latitude 24.8°N.</p

Factors affecting whether or not adult Hudsonian godwits carrying data loggers returned to the breeding grounds in the subsequent year, 2010–2012.

<p>Parameter estimates for a linear mixed-model predicting breeding ground return rates of individual godwits carrying data loggers. (<i>n</i> = 47).</p

Model and parameter estimates for models explaining the variance in the relative timing deviations exhibited by Hudsonian godwits during their annual cycle (2009–2012).

<p>Bold-font variance and t-statistic values were determined to be significant at <i>P</i><0.05 (<i>n</i> = 26).</p

Average key numbers of migration for swifts <i>Apus apus</i> as recorded using light-level geolocators, N = 6.

<p>Average key numbers of migration for swifts <i>Apus apus</i> as recorded using light-level geolocators, N = 6.</p

Model and parameter estimates explaining the variance in rate of change in timing deviations exhibited by Hudsonian godwits during their annual cycle (2009–2012).

<p>Bold-font variance and t-statistic values were determined to be significant at <i>P</i><0.05 (<i>n</i> = 26).</p

Deviations in timing from the population mean by nine individual Hudsonian godwits tracked during southward migration for three consecutive years, 2009–2011.

<p>Each bar denotes the number of days spent at a site and lines between bars the number of days spent traveling between sites. Red bars identify sites at which individuals became later relative to the population mean; blue bars those sites at which they became earlier relative to the population mean; gray bars those sites at which they neither became earlier nor later. The population average schedule for each year is shown in black.</p

Transformation of movement data of individual Hudsonian godwits into scores that reflect the accumulation or dissipation of lateness during their annual cycles.

<p>The first line displays the population mean (2009, <i>n</i> = 15) timing of arrival and departure for three consecutive sites in the godwit annual cycle. The second line displays the dates of the movements between those sites for one individual godwit, “HX.” The third line displays the relative timing of HX's movements in relation to the population mean. In this case, HX departed Beluga on 7 Jul and the population mean departure was 6 Jul; thus HX departed Beluga 1 day later than the mean (+1). HX arrived in Saskatchewan 3 days later than the mean and thus has a score of +3. In the fourth line is the rate of change of HX's movements. This score reflects the timing of HX's movements both in relation to the population mean, but also in relation to the timing of its previous movements. HX left Beluga 1 day later than the mean and, also, arrived in Saskatchewan an additional two days later than the mean (three days later in total), giving scores of +1 and +2. However, it departed Saskatchewan 3 days earlier than the mean, thus giving it a score of −6 (+3 to −3). Values calculated in Step 1 allowed us to account for inter-annual differences in the movements of the entire population. Values calculated in Step 2 allowed us to determine if an individual's rate of change from mean timing was part of an individually consistent schedule (i.e., an individual always departing three days later than the mean) or whether they reflected an individual becoming increasingly later (or earlier) — a potential manifestation of the existence of carry-over effects.</p

Factors affecting the breeding success of Hudsonian godwits (2010–2012).

<p>Parameter estimates for a generalized linear mixed-effect model with a binomial error distribution predicting the breeding success of individual godwits (<i>n</i> = 26).</p