The authors compile an interesting dataset that combines haemosparidian parasite lineage data with abiotic and biotic (host) data to determine the drivers of global haemosparidian parasite turn-over. They find that all combined variables have an effect, with geographic distance having the strongest effect. Of the host functional traits, they found that territoriality and resident non-migratory hosts were associated with high haemosparidian parasite turn over. Additionally, they found that mean temperature and seasonality of temperature were associated with parasite turn-over.

In general, I found that the manuscript was well written, easy to read and made clear points. There were a few points in the discussion where I thought that the statements made were more general than the results warrant (see line edits), but I think that some simple editing could address this. I also think that it could help the discussion to have a section on what species turnover means in the context of parasites and disease – what would the hypothesized consequences be of having more less parasite turnover?

Line 20: As you do in the discussion further down, I think it would be helpful to state ‘resident, non-migratory, species’ here. That would clarify what the term ‘resident’ is indicating.

Line 87: It might make sense to clarify that this hypothesis is based on the comparison between abiotic and biotic drivers. In other words, the way this is stated would suggest that you are testing that host factors among all other possible factors are the strongest drivers of patterns. Since it is not possible to test all possible drivers (e.g. what about parasite traits?), it makes sense to limit the hypothesis to the area you are testing.

Line 175-181: I am having trouble relating these results to the figure. I think this is because the figure 3a is somewhat difficult to interpret right now.

Figure 3a – the biol1-biol19 labels in the environmental PCA is confusing. The label of ‘biol’ to me suggests biology, and yet these are environmental variables. I looked and couldn’t find a key to enlighten me on what biol1-biol19 stands for. I would suggest changing the labels to something a bit more interpretable, and providing a key to what the variables are, at least in the supplement.

Line 205-207: This framing in the discussion should be set up in the introduction.

Line 209-210 and 219-221: These statements seem overly generalized. You found this pattern in one host-parasite system, and yet this statement seems to be claiming it for all host-parasite interactions. Please tone down the language to match the scope of this work.

Line 303: I think it would be worth noting that parasite traits are also missing from this analysis.

Line 304-317: I think just a little bit of editing here would be good to clarify the scope of the statements made in this section. I think the results are interesting, but it should be made clear that they apply to one type of host-parasite interaction, and thus can’t necessarily be generalized to all host-parasite associations.