seasonal patterns and processes of migration in a long-distance migratory bird: energy or time minimization?

Optimal migration theory prescribes adaptive strategies of energy, time or mortality minimization. To test alternative hypotheses of energy and time minimization migration we used multisensory data loggers recording time-resolved flight activity and light for positioning by geolocation in a long-distance migratory shorebird, little ringed plover Charadrius dubius. We could reject the hypothesis of energy minimization based on a relationship between stopover duration and subsequent flight time as predicted for a time minimizer. We found seasonally diverging slopes between stopover and flight durations in relation to the progress (time) of migration, which follows for a time minimizing policy if resource gradients increase and decrease, respectively. Total flight duration did not differ significantly between autumn and spring migration, although spring migration was 6% shorter. Overall duration of autumn migration was longer than that in spring, mainly due to a mid-migration stop in most ..., The data were collected using custom designed micro data loggers (MDLs) that recored acceleration, light during specified periods, air pressure, and temperature. The loggers were deplyed on little ringed plovers Charadrisu dubois, during the breeding season (May and June) in southern Sweden, and retrived 1-2 years later. 
The MDLs were pre-programmed with a calendar defining when to run the light level measurements for position estimates. This approach is different from conventional geolocators in that our loggers only measured sequences of daily light cycles for a limited number of consecutive days. The reduction of measurement periods of light-level substantially reduces the amount of data to be stored and prolongs operation time by minimizing the power consumption. In our study, we ran six measurement periods each of 5 days distributed over one year, starting on 15 July, 1 September, 1 November, 1 February, 15 April, and 5 May. The timing of measurement sequences was selected to matc..., , # Data from: seasonal patterns and processes of migration in a long-distance migratory bird: energy or time minimization

## The Xnnn\_acc.csv files contain acceleration data for migrating little ringed plovers *Charadrius dubius*

Description of the data and file structure

The csv-files contain nine columns of data (A-I), where each data row is the summary of acceleration data sampled for one hour, consisting of 12 samples. The data in each column are as follows:
(A) Date and time.
(B) Sequence number. Only of operational interest. The number is a control function that indicates that timing of the sampling routine works as expected. The number represents minutes passed since sampling was activated, truncated to 1 byte, i.e. when minutes is greater than 255, 256 is subtracted. The first values are 60, 120, 180, 240, and then they are 300-256 = 44, 104, 164, and so on.
(C) acc (0), acc(1), .., acc(5), columns C-H: Every 5 minutes a summary is stored for how many of 5 samples indicated a...