The Bar-tailed Godwit subspecies anadyrensis has indeed been elusive. Its taxonomic validity has been questioned then reestablished, and much speculation has been made in informal discussions about its non-breeding range. This MS provides the first confirmation of migration paths and non-breeding areas of the subspecies, and the data are placed well into context between the neighbouring subspecies. The implications of the findings are well outlined and the paper is very well presented.

Accordingly, I have mostly just minor comments, with one exception. As detailed below, the records used to include New Zealand in the non-breeding range are arguably not strong enough to warrant that. Recent plain white flag records are very likely to be Chinese birds that have lost a flag rather than NZ birds. Old records include a probable baueri on northward migration, a couple of flagged birds of unknown age, and a recovery of a bird marked only the previous season. Given that we now know (thanks to tracking in 2021) that young first-time migrants can spend time in Russia or spend the summer in Asia and make unusual and unexpected movements, unless a bird is confirmed as an adult, I don’t think it can be confirmed as truly being from Anadyr. The putative NZ-based anadyrensis shrinks to no confirmed adult that was not impaired by a satellite tag. I would advise discarding the recent records of white flags or stating clearly that their origin cannot be confirmed, and outlining the caveats about the other records. I would love for anadyrensis to be confirmed in New Zealand, and maybe genetics will enable this some time, but I would not be surprised if the non-breeding range does not span all of Australasia (which is what you currently suggest).

Line 205 It may be worth mentioning that the durations on the breeding ground for menzbieri means that most birds probably did not breed successfully. This would help comparisons with the earlier tracking published in Battley et al. 2012, when no birds bred successfully.

Line 229 Unfortunately, you cannot have confidence that a godwit with a plain white flag is from New Zealand. We have numerous examples of birds from other sites that use a white flag having lost a flag, thus appearing to be a bird from New Zealand. We know this happens because species that have never been caught in New Zealand, let alone flagged, have been reported as New Zealand birds with a single white flag (e.g., Grey Plover, Great Knot). We probably have more records of shorebirds with white flags that are not from New Zealand than you have of white flagged godwits in Kamchatka. Given that we have been colour-banding in NZ since 2004, and using ELFs since 2005, it is highly unlikely that plain white-flagged godwits seen recently will be NZ birds. There are a few individuals still around with plain flags, but they are vastly out-numbered by individually-marked birds. I would exclude these recent records as being of confirmed origin.

Line 241 Were the birds that stopped short before the Yellow Sea carrying 10 g or 5 tags? We had clear examples of male baueri being impaired by 10 g tags in 2007.

Line 250 Perhaps reiterate that the difference in breeding duration probably reflects a difference in breeding success. We don’t know whether the timing of menzbieri would be the same or different in a year when all bred successfully.

Line 255 The absence of menzbieri on Kamchatka is also supported by Battley et al. 2012.

Line 259 I’m a bit uneasy about referring to these birds as “banded anadyrensis” when there is no way to diagnose or discriminate the subspecies. “Assumed anadyrensis” would be more accurate.

Line 260 The claim that anadyrensis occurs in New Zealand needs close scrutiny. Riegen 1999 cites two NZ birds seen in Russia, but one was on Bering Island (east of Kamchatka) on northward migration (which we know baueri can do) and was more likely an Alaskan bird than a Russian. The other was recovered on Kamchatka in October, so was likely a bird that had spent the summer in Russia. However, it was banded only the previous non-breeding season as an apparent adult. No wing moult data were evidently collected to help verify the age, but the tracking of first-time northward migrant godwits from NZ in 2021 showed that these birds may make movements not seen in adults. One bird spent the breeding season in Russia and subsequently moved to Alaska, while another spent a while in Russia before moving east. Others summered in the Yellow Sea. Without being able to prove that the bird recovered in Russia was indeed an adult doing what it normally does, it is possible that it was not an anadyrensis. These data are unpublished, though the tracks are available online, but if you wanted to make reference to is you should communicate with Bart Kempenaers about it for a pers. comm.

This leaves the records of probably 2 birds in Schuckard et al. These could be from NZ, but I think that the black-white Chongming combination may have been active then. In any case, the true age of these birds is unknown. There is one other unpublished record of an NZ bird in eastern Russia, a male tracked by backpack in 2007 (Z5). This bird had a severely impacted-on migration, spending a month on an atoll in Micronesia, then stopping in Okinawa, then finally reaching the Yellow Sea and departing for Russia on 19 May. We never knew how much or little to trust this bird’s route and destination given how screwy its trip to Asia had been (this was almost certainly a transmitter effect). This is the bird mentioned in Tomkovich 2010.

Putting this all together, I would argue that there is no conclusive evidence to say that anadyrensis reaches New Zealand. I wouldn’t say it is not possible, but I don’t think that any of the records presented here establish it, and any mention of New Zealand needs to recognise the caveats. I would mistrust most the recent plan white flag records, but Bart’s bird also shows that baueri (subsequently departing from Alaska) can occur in Russia in the summer. If you were to say that the confirmed non-breeding range includes NW and northern Australia, and that it is unclear whether the range extends to eastern Australia and New Zealand you will probably make only Rob Schuckard unhappy. You could still mention the older flag sightings along with bird-age-related caveats.

Line 269 You had 2/24 tracked birds going to Anadyr, but we also had all those from the earlier tracking that did not go to Anadyr, so perhaps a more accurate figure would be 2/35 (or do you have more birds not in this study?). I don’t think it really affects the numbers you will end up with.

Line 276 I think the writing states something not quite correctly (it implies you have 24 anadyrensis) but would be fixed as “a small proportion of bar-tailed godwits are anadyrensis that spent…”

Line 302 Change “two-species comparison” to “two-subspecies comparison”.

Line 309 The A in Anadyrensis is missing the italics.

Line 320 Change “arised” to “arose”.

Line 323 Change “data is” to “data are”.

Line 352 Lappo et al. 2012 is given as “in press”.

Line 394 There is one T too many in Clive Minton’s initials.