Nest Change and Individual Fitness in a Scopoli’s Shearwater Population: A Capture-Recapture Multistate Analysis

Round 1

Reviewer 1 Report

Dear authors,

I think that the aim of the manuscript is very interesting and also the analytical approach that you chose is very appropriate. However, I have some concerns about the suitability of your chosen specific approach (model structure) to test your hypotheses.

Find below some of my concerns and other suggestions. As you will see, some of my comments or suggestions are purely esthetics or aimed at improving readability of the manuscript, whereas others are more critical. I hope my comments will be useful.

 General comments:

·         I think that the model structure you have chosen is not the appropriate one for answering some of your hypotheses. If you want to assess the consequences (or causes) of changing nest in breeding success or survival, you should keep the probability of changing nest free (as all the other parameters: survival or breeding success). Otherwise, if you prefer to evaluate only the consequences of changing the nest “at least once”, you should redefine your hypotheses. For example, if “there are two types of individuals, those that change nest and those that no, and if they differ in their average survival or breeding success”.

·         In my opinion, writing should be improved to help reader get the ideas, methods and results you obtained.

 Introduction

·         I think that an effort should be made to relate clearer what other have previously found and what are your main questions to answer (in this case your three hypotheses to test).

·         L 83-85. In my opinion your model structure does not allow you to test these hypotheses.

·         L-115-118. I would specify in which sense survival and mate or nest change are correlated.

·          L. 119. “…from one season to another…”. I do not think that you are testing that with your actual model structure.

Methods

 ·      This is not relevant and just my personal opinion, but I am not sure that you should include a specific section with definitions. I think that it would be more appropriate to introduce all these terms when you use them.

·         L. 130-131. I think that the definition of BSC is not clear.

·         L. 130-131. What does it mean -B

·         L132-134. When defining “Winner” you said that is different from the “previous” but when you define “Loser” you do not specify that. I would define both type of individuals in the same manner to avoid confusion.

·         L. 144. Not only in the Canaries but also further south in the Atlantic waters (one of the references you already cite and De Felipe et al 2019. (https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.5501)

·         L. 153. I would provide references (for regular sites change and nest tenacity differential in sexes).

·         L. 151-161. I am not sure that all this information should be placed here and this way. If you want to summarize known information, perhaps would be more adequate to provide a table. You could also have a look on this reference Sanz-Aguilar et al 2011. https://doi.org/10.1890/09-2339.1

·         L- 162-186. An effort should be made in rephrasing and explaining the study system and monitoring in a clearer way (which study sites, how many years, data collected each year, etc..).

·         Figure 1 may be improved. At least you should show the two studied colonies.

·         176-178. These two sentences should be rephrased to clarify the message.

·         L.180-184. The two sentences are repeated.

·         184-186. Could you clarify the number of captures and recaptures? The number of recaptures that we have for each individuals is crucial to assess our power to test some hypotheses.

·         Even if not important, I think that it would help readability if you present sample sizes in the same order (i.e first number of females then males or viceversa, but always the same).

·         NC matrix. Why do you include an arrow in the probability?

·         BSC matrix. The headings of the matrix are wrong. You forgot the name of the first column.

·         Observation matrix. Perhaps the headings could be improved to clarify the meaning. Instead of saying the name of the state, specify what are you really observing, i. e. Individual found in the first nest where started breeding and in the previous occasion failed breeding.

·         Figure 2. I found this figure confusing. Transitions matrix show the transitions “from” different states at time t “to” other states at time t+1; so I struggle to understand why do you have transitions at time t. 

·         251-260. It is not clear to me how you analyze age. How many age classes etc?

·         272-273. GOF analyses should be done on the first place, so probably would be more adequate to talk about GOF at the beginning of this section.

·         Methods section should be improved to clarify the analytical approach used for answering each hypothesis. Especially important is that you clarify the codification of the events and states. I found difficult to understand when you deal with “previous” or “current” information. 

 Results

·         L. 297-301. How do you explain that males showed a different average breeding success than females?

·         L. 288-295. I would show the results that you obtained for both sexes in a clearer way.

·         Figure 3. In y-axis says “current breeding success” and not previous. I do not know if is an error. As previously stated, in my opinion an effort should be made in clarify how you try to test each one of the hypotheses.

·         L. 304. Age analyses should be clarified as previously stated.

·         Tables should be improved. Perhaps reduce the number of models and show all the others in Supplementary material. Parameter’s ranking should be explained also in the methods section.

·         Figure 5. In my opinion this Figure may be improved.

·         I have also some other general doubts. 1) How do you deal with birds in sabbatical? 2) Is there the possibility that you missed some birds? Can they be breeding outside your study area but at the same colony?

Others

·         L. 491. Change “Godness” by “Goodness”

·         I think that your data set is very valuable, but I am not sure if we can talk about long-term data when we refer to nine years for such a long-lived species.

Author Response

Author Response File: Author Response.pdf

Reviewer 2 Report

This is an interesting paper. Methods and results are presented properly. I have onlu few minor comments. All are marked in the PDF version of the maniscript.

Comments for author File: Comments.pdf

Author Response

See comments in the attached file

Author Response File: Author Response.docx

Reviewer 3 Report

The ms deals with the effect of nest change in Scopoli’ shearwater. The authors used for me not familiar statistical approach, but it seems that some results were clearly achieved. Therefore, my major issue is to clearly explain the results of the tables in the statistical analyses caption (2.3). For me, it is not clear, how exactly were compared values within row and columns. There should be a clear explanation what these values in tables exactly mean. Therefore, please put more effort to explain the philosophy of the meaning of the values that are compared. Maybe, it would be beneficial to add some table with explanation of the exact values that were achieved. For me, it is not also clear, how the diagram in Table 2 was achieved (i.e. how these results are connected with previous tables mentioned in Statistical analysis). In my opinion, this is the most important issue of the manuscript.

I have also some minor changes that would improve the manuscript:

L11 – Delete redundant space in the beginning of the abstract.

L78 – Haematopus ostralegus in the bracket should be in italic.  

L187 – Please, remove double dot after Statistical analyses.

Author Response

See comments in attached file

Author Response File: Author Response.docx