In this work the authors investigate phenotypic plasticity in hibernation phenology related to weather in both sexes in Columbian ground squirrels, as well as the fitness consequences of early emergence (relative to females) in males. This is a solid work (by combining two study areas, several study years, phenological and reproductive success data in both sexes and its relationship with climatic conditions) that has both evolutionary (protandry) and conservation (consequences for population sustainability) implications. I have enjoyed reading and have found no major theoretical or methodological concerns, so I have only a few minor suggestions to make. In fact, I think I have never suggested so few changes in a review, so I congratulate the authors.

Line 53 Please add some references to these studies.
Abstract and lines 100 and 127... one or two populations?.
Lines 137 and 157 Please add coordenates of the study areas. A map of these areas maybe in the Sup material would be also welcome
Line 150. Authors refer to study 32 for field protocols, but some further details would be welcome here to facilitate comprehension of the text. For example, 1) How often were the surveys to detect emergence from hibernation (daily, weekly?) 2) were individuals repeatedly capture to determine when they are reproductive capability/readiness? 3) territoriality could be briefly defined (in addition to mention reference 33). I mainly work with birds and these gaps somewhat hampered the comprehension of the text
Line 243-244 Variance inflation was evaluated, but, please, confirm that there was no issues with this
Figure 3 I think that the figure would be visually more informative and easily interpreted if both axes have the same initial (90) and end (150) points
Table 2 P values are shown in table 1 but not in table 2. Is this a typo or is there a reason?