The Foraging Window for Greater White-Fronted Geese (Anser albifrons) Is Consistent with the Growth Stage of Carex

Round 1

Reviewer 1 Report

I found the article interesting to read. While the background and discussion is overaly well-written, I think the methods and results sections needs to be tightened up. these include specifying the tests that were done, and some adjustments to figures and tables provided 

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Reviewer 2 Report

In this study, scan sampling and focal animal sampling were used to record the foraging behaviors of wintering greater white-fronted geese at Shengjin Lake from October 2017 to April 2018, and the plant height and water content of Carex were surveyed simultaneously. This manuscript is well organized and the drawn conclusions are coherent with the obtained results. The references should be updated to include more recent studies. Their results showed that Carex had two growth periods at Shengjin Lake, and the pecking rate and foraging time budget of greater white-fronted geese were higher during these two periods.

Lines 32 – 33: The references should be arranged alphabetically.

Lines 82 – 87: To explain better your hypothesis and predictions.

Lines 250 – 251: I think that you should add this important and recent reference as example to support your sentence “The results of this study provide insights that can inform the development of wetland management strategies.” I would like to suggest:

Ancillotto, L., Bosso, L., Salinas-Ramos, V. B., & Russo, D. (2019). The importance of ponds for the conservation of bats in urban landscapes. Landscape and Urban Planning, 190, 103607.

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Reviewer 3 Report

Comments

Suggestions

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Reviewer 4 Report

Reviewer comments on the “Foraging window of greater white-froned geese (Anser albifromns) consistent with growth of Carex” by Zhong et al.

Abstract

Line 16: Says that Greater White-fronted Goose (GWFG) relatively dependent on Carex in the Yangtze River floodplain and no mention about what other plant materials and their relative preference in the entire study.

In Line 24 the authors have mentioned that the pecking rate and foraging time budget of GWFG was higher during the two Cerex growth rate stages but in the line 232 these rates were also higher during early spring and autumn and during such period sedges had lower water and nutrient content. It seems contradictory statement!

Introduction

Line 57 “The resource availability hypothesis (RAH) proposes that higher levels of herbivores forage…..”Not getting what those higher levels of herbivores are?

Line 65 ‘Seasonal water level…..floodplain [13]. But the reference 13 talks about resource availability and plant antiherbivore defence and not about Yangtze river floodplain. Pl. Check the reference. 

Materials and methods

Line 91. “It is also an important wintering ground for geese…’You mean to say Asian Bean Goose (ABG) including the GWFG. Because the reference 23 talks about ABG.

Does geese feed only on exposed sedge and not the portion below water surface?

Line 120: The pecking rate was defined ….as the times of pecks. Instead of ‘times’ mention ‘number of pecks per..

Line 121: A total of 216 data were recorded during the entire wintering season. What does 216 means and what type of data collected?

Line 123: Nine quadrats (0.5 m x 0.5 m) were randomly…plant height and temperature in …..

In fact I do not see any analyses involving temperature and if its is so better remove from methodology section.

Similarly in Line 134 Student’s t-test was used…. No such analyses involving t-test in results section.

It seems that the researchers have measured the height of each plant (N=216). If so how did they arrive at a conclusion of how geese choses to forage on sedges of preferred or particular height in real time when the studies carried out?

Results

 In Figure 2 (a, b and c represent early winter, middle winter and late winter; 1….). It is quite difficult to infer from such short abbreviations instead below each bar you can write as follows

1^st  Early Winter, 2^nd Early Winter, 1^st Middle Winter, 2^nd Middle Winter, 1^st Late Winter and 2^nd Late Winter. It becomes easier for the reader to infer the charts at ease.

Furthermore, I do not see any result pertains to your a1 i.e., 1^st Early Winter? Why?

I do not find any mention of Table 1 in the main text related to Pearson correlation.

Furthermore how can you correlate Pecking Rate with Water Content as the later is an independent variable and comparing Pecking Rate and Foraging behaviour time budget with Water content of the sedge seems absurd.

As per results the bimodal growth distribution of sedges coincides with arrival of geese in Shengjin Lake and if so the Geese should depart the site during low water level season period and then comes back when water level increases? Even if they stay there during lean water season what they feed upon? Still sedges or they prefer to forage on other food items as you have mentioned in your abstract (lines 30 and 31) that ‘During the foraging windows, geese changed their foraging strategies to obtain…’

Normally, in avian foraging ecology when food is in abundance, the foraging birds maximise their energy level quickly in short duration. But in contrary, the geese’s pecking rate and the time budget were highest between December and March when plant height and water content of the sedges were higher? Could you please explain why this inverse trend is?  [Pl. refer your statement in lines 194 to 197]

Line 209: As a trade-off….. I do not get this statement clearly and furthermore it only hypothetical and no date to substantiate your claim.  

Statements made about the geese choosing to increase their pecking rate and foraging time (in Lines 217 to 219) budget during rapid plant growth stage and your statement in Lines 232 to 234 contradict each other.  

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Reviewer 5 Report

Introduction
check for grammatical errors

41-43- Rephrase the sentence

43-44- Add references

48-50- Add Aarif et al., 2021( https://doi.org/10.1016/j.gecco.2021.e01518) as reference

51-53- The statement seems unwanted there, since the sentences above are explaining what you have already mentioned in line 43-44 . Rephrase the sentence and replace at 43-44 to ensure the aesthetic flow to next paragraph.

 58-59- Add references

 59-61- Remove the sentence since it is affecting the logical flow of the paragraph. Mention about the effect of plant height and water content on the pecking rate after line 61-62.

 87- Delete the irrelevant concluding sentence after objectives.

Materials & Methods

89- Add coordinates of the study area

I am really surprised that why authors are didn't employ video-recording methods to study the foraging behaviour of anatidade !  

Statistical analysis and results are fine 

Discussion

The discussion part needs extensive revision, since the findings are not discussed in a convincing manner with proper references. Try to maintain a logical flow and avoid unnecessary and repetitive statements.

192-194 – Delete this unnecessary sentence repeating, what you have already stated in the previous lines.

200-204 - This makes no sense to me. Rephrase and make it sensible.

209-211 – “As a trade-off between food quality and quantity [32], greater white-fronted geese may reduce foraging in each surveyed area and shift to another area to obtain sufficient energy”- What is the relevance of this statement here?

214-216 – “Therefore greater white-fronted geese that depend on sedges may expect more food and energy in-come” What do you mean by this sentence here?

220-221- How lignin and cellulose affect the food availability of plants?

227-230- It seems the authors added irrelevant points to elaborate the discussion or else how the migration distance matters here?

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Round 2

Reviewer 4 Report

I have gone through the revised manuscript and corresponding author's letters wherein he/she has given info about hoe the team responded to my concerns by addressing most of the relevant issues. Therefore, I am of the opinion that the manuscript in its present from may be accepted for publication. 

Maheswaran