Experiments Reveal That Search Image Might Be Responsible for Seasonal Variation in Nest-Predation Rates
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsPlease see attached.
Comments for author File: 
Comments.pdf
Author Response
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Author Response File: Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsIt is heartening to see a long-term study, given the general lack of support for such work by many institutions and funding agencies. For this system, I feel that the interpretation is justified, and the work is well presented. Some comments on the text follow.
Materials and Methods, Section 2.3 Predator identification
Here you comment that Stoats and Least Weasels are rodent specialists; are any data on rodent populations available, and did these show any influence on the frequency of predation by these mammals?
Discussion
In some years, major losses can be caused by unpredictable events such as adverse weather during the breeding season. So survival in a given year can be a "lottery" not solely dependent on relatively predictable factors such as predation. Was variable weather a factor over the study period?
It would be interesting to base comparisons on markedly seasonal vs less seasonal environments, where the adults may have more scope to be flexible in the timing of breeding attempts. A thought for a future review.
In the references, there are some problems in presentation with text that has presumably been downloaded from another source and not re-typed. These issues are listed below with the relevant reference numbers:
1. Where doi information is provided, surely the inclusion of the <Go to ISI>://WOS etc is superfluous and should be deleted (easily visible).
2. Geographical names appear with lower case first letters, which should be upper case: 26, 32, 40, 43, 47, 83, 90, 102, 109, 122, 123
3. Specific names appear in lower case when genus should begin with upper case, and are not italicised: 25, 34, 40, 45, 53, 63, 81, 8490, 101, 117,122,124
3. In most cases, journal titles have been abbreviated but the following appear in full: 4, 12, 34, 74, 103, 106, 110
Comments for author File: Comments.pdf
On the edited text attached, I have suggested some changes to language where it seems that the choice of words could be improved, or a passage rephrased so that it is clearer to the reader. A few minor typos are also corrected; generally the text is almost free of such errors, and is entirely readable.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThis is a usueful contribution to predation ecology. The rusults are however not fully diplayed, so also the discussion can be slightly modified.
Page 190: Various predator species occurring in the study area are listed. What about the alien carnivors (American mink, raccon dog, racoon), which are usually the most desctuctive to nests of terrestrial and water birds in Central Europe.
Page 192: Stoats and least weasels are not rodents!! No mention is made to species such as Sus scrofa, cats and dogs. They may become serious nest predators to some bird species.
Page 2003: It is stated here that the survey was conducted between 25 May and 20 June, but in Fig 1, the distribution of breeding pairs recorded at 140 point is from the third decade of March to the third decade of August. How the points were distributed over the time?
In 'Results' section to distinguish between mammalian and avian predation is too general. Are the authors able to provide details on the predator species. I realize that it was not possible to identify the predator species in many cases, but certainly there were known cases of predator species, e.g. Jay - 15%, Crow - 10%, Least Weasel - 10%....Unknown predator species - 30%.
Fig. 3: It would faciliate a comparison if a similar graph is shown here for the artifical nests. I also advice to clearly separate failures in ground nesting birds from those nesting in trees and shrubs.
In 'Discussion' section it would be considered that in the case of early breeding the shortage of food might be an important factor causing the losses, while in the case of late breeding, the time might be such factor (chicks might have not enough time to aquire enough stength and skills to survive). It should be also considered that the highest predation rate in the middle of the breeding season is simply because the number of available nest with chicks or eggs is the highest in the middle of the breeding season, i.e. in the time when the amount food available for most birds is the highest.
Author Response
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Author Response File: Author Response.pdf
