Assessing Survey Design for Long-Term Population Trend Detection in Piping Plovers

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript was written in a comprehensible and very detailed manner, especially regarding the methodology, results, and discussion sections. I have no major considerations to make, only two suggestions:
In Table 1 it is not clear what the “-” signifies. Does it correspond to 0 individuals or was there no census?

Figure 1 has low resolution and definition. I also consider it important to include a map of North America, to better contextualize the study area globally.

Author Response

Thank you very much for your thoughtful review and helpful suggestions. I clarified the meaning of the “–” in Table 1 by adding a note to the caption, and I improved the quality and clarity of Figure 1 by providing a higher-resolution version and including a map of North America for broader geographic context. I greatly appreciate your careful attention to detail, which has strengthened the manuscript.

Reviewer 2 Report

Comments and Suggestions for Authors This is a really valuable study! It's not only of great significance for species conservation but also provides a good monitoring window for the study of geographic ecology on fragmented islands. The research is carried out based on long-term data surveys and nicely discusses two hotspots in current research - the increasingly popular Bayesian methods and their differences from traditional frequentist approaches. Kudos to the authors for completing this excellent study! Although I'm not a native English speaker, I think the language expression in the paper is fine, and I generally appreciate this research a lot.

 

To better communicate with the authors, here are two simple questions:

 

1. In the monitoring of migratory birds, besides the target bird species, have other birds and organisms been considered? Are there more detailed characterizations of their specific activities and behaviors? If not yet covered, this might be a direction for follow-up research.
2. Regarding the study of islands, apart from area, has the landscape composition (such as shape, habitat landscape patterns, and other spatial elements) been considered? Especially landscape dynamics, and the distance between the island and the mainland - is it necessary to include the accessibility of target birds in specific comparisons? Additionally, regarding whether similar patterns exist in other taxonomic groups besides the target birds, it would be great to see a brief explanation in the discussion section.

 

Thanks again to the authors for their efforts, and I look forward to the further improvement of this research!

Author Response

Thank you for your kind and encouraging comments on our study. We are glad to hear that the manuscript’s focus on species conservation, geographic ecology, and Bayesian approaches resonated with you. Your questions and suggestions have been very helpful. In response, we added discussion about extending the analysis to multispecies and behavioral data, referencing our related work with occupancy modeling on Whiskey Island, and we clarified how future studies could incorporate landscape composition, spatial dynamics, and island connectivity. We also included a brief discussion of similar spatial patterns in other taxa. These revisions have improved both the depth and applicability of our work, and we are grateful for your insightful feedback.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Review of Assessing Survey Design for Long-Term Population Trend Detection in Piping Plovers by Bohnett et al.

General Comments

            This is an interesting, generally well-written paper that describes an important information need. There are a lot of statistics presented that inform how to conduct future monitoring studies, but the authors never provide estimates of trends in plover numbers during their study and how different sampling schemes would affect those estimates. That seems like a serious shortfall. If the authors are unable to do that for some reason, they should state that. Without these trend estimates, the paper doesn’t seem to have tangible real-world implications.

Specific Comments:

• Section 1, line 59. I think “and” is more appropriate than “or” in this list of considerations.
• Section 1, line 98. I suggest changing the wording of this sentence to: “Populations of the piping plover (Charadrius melodus), a migratory shorebird, are highly sensitive to even minor declines in their vital rates, such as adult and juvenile survival.”
• Section 1, line 112. Provide a reference for Moran’s I.
• Section 2, line 131. Provide the date for the Gulf oil spill and a reference that describes it.
• Section 2, Figure 1. Provide a more informative figure (perhaps a line drawing) that shows detail of the islands as well as a zoomed out map showing their location. The labelling of the figure provided is difficult to read.
• Section 2, line 152. Isn’t the actual human recreational use rather than the management of it the more important impacting factor? Although recreational use is significant, I would think that habitat alteration along the coast and associated watersheds would have larger impacts.
• Section 2, line 154. Replace “and” with “that?”
• Section 2, line 155. What does “Understanding the species' … scenarios” mean?
• Section 2, line 165. Shouldn’t “the island” be changed to “each island?”
• Section 2, line 167-168. What other focal shorebird species were surveyed? Make it clear that the plover data were collected as part of a broader shorebird effort. I would delete the word “exact” because birds must have been moving and presumably surveyors measured an approximate location using a handheld GPS unit.
• Section 2, line 171. Change “plover” to “plovers.”
• Section 2, line 173. What specific behaviors were catalogued?
• Section 2, line 173-174. Are the number of surveys provided here for all six years of the study? So, for West Raccoon and East Raccoon Islands fewer than one survey per year were conducted?
• Section 2, line 177. Add a period at the end of the sentence.
• Section 2, Table 1. Several comments: (1) Are these really the number of counts (i.e., surveys) or are these the number of Piping Plover observations made during counts? (2) Line 162 states that surveys were conducted in 2013-2018, but the table shows data from 2012-2019. (3) The East Raccoon label at the beginning of the second row of the table has something superimposed over the word “East.”
• Section 2, Figure 2. The caption indicates A and B sets of grids, but there are no labels on the figure. Either add labels or replace “A” and “B” with “left” and “right” in the caption.
• Section 2, line 199. Aren’t the models for imperfect detection equations 3 and 7, not 3 and 9?
• Section 2, line 205. Where is equation 1?
• Section 2, line 228. Provide a reference for Queen’s neighborhood matrix.
• Section 3, line 296. There are no bolded results in Appendix Table 2.
• Section 3, line 334. There is no Figure 4. There is a table that is labelled Figure 3. This should be Table 2.
• Section 3, Figure 3. This is a table (should be Table 2), not a figure even though it is an image. At the top of each sub-table, identify what the numbers in the table represent.
• Section 4, line 375. Change “dynmic” to “dynamic.”
• Section 4, line 482. Here “ĉ” is used instead of “c-hat.” I would use “ĉ” throughout.
• Section 4, line 488. “Scarcity” is misspelled.
• Section 4, line 500. This is the first time that the term Frequentist is used. It would be useful for the authors to point out, in the methods section, the difference between Frequentist and Bayesian models.
• Section 4, line 536. Something is wrong with this phrase “studies using have shown.”
• Section 4, line 538. Replace “Ot” with “It.”
• Section 5, line 549-550. This sentence should state what the models and analysis were applied to.
• Appendix Tables. For all, add “A” and “B” to the full grid and plover subset portions, respectively. References in the text are to Table #A or B, but without the labelling, the reader won’t know where to find the information.
• Appendix Table 2. Several comments: (1) I see no entries in bold in this table. Were there no best-fit models? (2) What are the values to the right of the means, labelled “(2.50-97.50%).” (3) Add a footnote that provides definitions for all abbreviated variables mentioned in the table (Psi, Col, Ext, P, MLEs).
• Appendix Table 3, line 619. Several comments: (1) Which results are for the Makenzie and which for the Bailey GoF tests? (2) There seems to be a word missing after “unmarked.” (3) “The Bayesian Dynamic …” sentence isn’t complete. (4) Add a footnote that provides definitions for all abbreviated variables mentioned in the table (p-value, c-hat, Chisq, fT). Note that in the caption “Chisq” is mentioned as “Chi-squared” and “fT’ as “ft.”

Author Response

Thank you for your detailed and constructive review. Your comments were instrumental in improving both the clarity and the practical implications of the manuscript. We carefully revised the text to explain why trend estimation in plover numbers was not feasible with the available data and emphasized instead how our dynamic occupancy modeling and power analysis inform realistic monitoring strategies. We also addressed each of your specific comments, from wording adjustments to figure/table improvements and additional references, which have made the manuscript more precise and user-friendly. I deeply appreciate the time you invested in providing such thorough feedback.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

The authors did a good job responding to my comments. I have only one follow-up to a comment I made on the original ms. 

Original comment: 

• Section 2, line 173-174. Are the number of surveys provided here for all six years of the study? So, for West Raccoon and East Raccoon Islands fewer than one survey per year were conducted?

Either I do not understand what information the sentence is intended to convey or the authors did not understand my comment. Since there were six years of study, there should be at least 6 surveys conducted for each island. The sentence indicates there were 5 and 2 surveys conducted for West Raccoon and East Raccoon Islands, respectively. New Table 1 indicates that there were many surveys conducted at each site. How do the authors reconcile the statement with the information in new Table 1?

Author Response

Thank you for catching this! It looks like the changes I made previously to delete that sentence did not actually get saved. I apologize for the oversight and I’m glad you spotted it before proofreading. I really appreciate the effort you put into carefully reviewing the manuscript.