Influence of prey patch dispersion and density on energy expenditure for guillemots and razorbills.

<p>Simulations of proportional daily time budgets and daily energy expenditure (DEE) for guillemots (A, B) and razorbills (C, D) where: (1) prey becomes more patchily distributed requiring more flight time between patches and more foraging time to meet energetic needs (A, C); and (2) prey decreases in density within patches, requiring more foraging time, but distribution is unchanged (B, D). Asterisks indicate the proportion of time activity budget which is the mean across all recoded activity budgets of birds of each species, respectively (see Appendix S4 and S5 in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0079915#pone.0079915.s001" target="_blank">File S1</a>).</p

Parameter estimates used in the bio-energetics model for adult birds.

<p>See text and Appendix S2 in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0079915#pone.0079915.s001" target="_blank">File S1</a> for metabolic relationships.</p

(A) Mean prey species by frequency, energetic proportion, and size [31] for adults used in the bio-energetics model, and (B) prey species by frequency, energetic proportion for chicks used in the bio-energetics model.

<p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0079915#pone-0079915-t002" target="_blank">Table 2A:</a> A division of 60 mm was chosen for 0-group sandeel and 1+ group sandeel based on fish collected from flight-netting puffins <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0079915#pone.0079915-Wanless1" target="_blank">[22]</a>. Proportions for guillemots are expressed as means across years of data collection – see Appendix S3 in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0079915#pone.0079915.s001" target="_blank">File S1</a> for full data.</p><p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0079915#pone-0079915-t002" target="_blank">Table 2B:</a> See Appendix S1 in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0079915#pone.0079915.s001" target="_blank">File S1</a> for more information on decisions used on raw data from all-day watches to estimate prey proportions for chicks.</p>a<p>Based on regurgitated samples from the Isle of May 2003 - 2007 <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0079915#pone.0079915-Wilson3" target="_blank">[31]</a>.</p>b<p>Using the same 0-group prey size as guillemots.</p>c<p>Mean length value converted to energy <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0079915#pone.0079915-Wilson3" target="_blank">[31]</a>.</p>d<p>Information on the size of prey items deleivered to chicks are presented in Appendix S1 in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0079915#pone.0079915.s001" target="_blank">File S1</a>.</p

Winter survey sites for colour-ringed shags.

<p>Black points denote positive survey sites, where at least one adult colour-ringed shag known to have bred on the Isle of May was resighted in at least one winter 2009–2012. Sites are defined as roosts separated by ≥1 km.</p

Prey capture rates from the bio-energetics model from 10,000 MC simulations assessed under a standard diet for both species (prey sizes, prey proportions).

<p>Prey capture rates from the bio-energetics model from 10,000 MC simulations assessed under a standard diet for both species (prey sizes, prey proportions).</p

Within-winter repeatability (R_w) of the distance from the Isle of May at which colour-ringed adult shags known to have bred on the Isle of May were resighted during winters 2009–2012.¹

1<p>Repeatabilities were estimated across the whole winter period (1st September – 31st March, 0% movement boundary) and across increasingly restricted time periods defined by the 30%, 60% and 90% movement boundaries (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0098562#pone-0098562-g002" target="_blank">Figure 2</a>). Vi and Vt are the within-individual and total variances in distance from the Isle of May respectively, and p is the probability that the estimated Rw could be obtained by chance. The numbers of individuals, resightings and sites are the totals included in each analysis, with “sites” defined for descriptive purposes as the number of known roosts separated by ≥1 km. Distance range is the maximum coastline distance covered.</p

Among-winter repeatability (R_a) of the distance from the Isle of May at which colour-ringed adult shags known to have bred on the Isle of May were resighted during winters 2009–2012.¹

1<p>Repeatabilities were estimated across the whole winter period (1st September – 31st March, 0% movement boundary) and across increasingly restricted time periods defined by the 30%, 60% and 90% movement boundaries (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0098562#pone-0098562-g002" target="_blank">Figure 2</a>). Vi and Vt are the within-individual and total variances in the distance from the Isle of May respectively, and p is the probability that the estimated Ra could be obtained by chance. The sampling interval is the upper and lower 95% intervals of the Ra estimates obtained by resampling a single resighting of each individual within each winter. The numbers of individuals, resightings and sites are the totals included in each analysis, with “sites” defined for descriptive purposes as the number of roosts separated by ≥1 km. Distance range is the maximum coastline distance covered.</p

Summary of the numbers of colour-ringed adult shags known to have bred on the Isle of May that were resighted during winters 2009–2012 across all survey sites.¹

1<p>Grand totals are of unique individuals resighted across all winters, so do not equal the sum of individuals resighted within individual winters. Interquartile ranges (IQR) are shown in parentheses. Positive survey days are days on which at least one colour-ringed shag was resighted (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0098562#pone.0098562.s001" target="_blank">Figure S1</a>). Positive survey sites are roosts separated by ≥1 km where at least one colour-ringed shag was resighted on ≥1 date (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0098562#pone-0098562-g001" target="_blank">Figure 1</a>).</p

Within-winter repeatability (R_w) of the distance from the Isle of May at which colour-ringed adults shags known to have bred on the Isle of May of different sexes and ages were resighted during winters 2009–2012.¹

1<p>Repeatabilities were estimated across the whole winter period (1^st September-31^st March, 0% movement boundary) for each year. V_i and V_t are the within-individual and total variances in distance from the Isle of May respectively, and p is the probability that the estimated R_w could be obtained by chance. The numbers of individuals, resightings and sites are the totals included in each analysis, with “sites” defined for descriptive purposes as the number of roosts separated by ≥1 km. Distance range is the maximum coastline distance covered. Ages are years since hatching at the start of each winter. The analysis includes individuals ringed as adults and therefore of estimated age: for individuals ringed as chicks only, see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0098562#pone.0098562.s008" target="_blank">Table S1</a>.</p

Movement boundaries.

<p>The percentages of colour-ringed adult shags known to have bred on the Isle of May that were resighted on or near the Isle of May and at an alternative winter site during winters A. 2009–2010, B. 2010–2011, and C. 2011–2012 that were away from the Isle of May on progressive dates. Dotted lines indicate 10% intervals, dashed lines denote the movement boundaries used to subset the data for repeatability analyses (0%, 30%, 60%, 90%).</p