Interesting/Little Known introduced populations

[Andrew Swales]

Pardon my ignorance, but this photograph is among the first results upon using the search term, 'mandarin wood duck hybrid', and in this old forum thread, someone claims that that is exactly what the photograph shows. Is it possible to tell me what the actual identity of the bird in the photograph is?

My feeling is that this could be a very clever and convincing photo-shop. The head (from a sex-changed or partially eclipsed Mandarin?) feathers on the cape, both at the cheeks and on the nape, do not seem to fit/flow quite right onto the Carolina parts...

 

[Chlidonias]

My feeling is that this could be a very clever and convincing photo-shop. The head (from a sex-changed or partially eclipsed Mandarin?) feathers on the cape, both at the cheeks and on the nape, do not seem to fit/flow quite right onto the Carolina parts...

I'd be inclined to agree with that. The head doesn't seem to sit right with the body.

 

[FBBird]

Yes; I have heard of that before. Is there a peer-reviewed journal article that discusses the subject?

If you google it, you'll find a lot of references. Nobody has ever produced convincing evidence of a Mandarin hybrid. Any photographs I have seen, were hormonally compromised Mandarins.

 

[FBBird]

Pardon my ignorance, but this photograph is among the first results upon using the search term, 'mandarin wood duck hybrid', and in this old forum thread, someone claims that that is exactly what the photograph shows. Is it possible to tell me what the actual identity of the bird in the photograph is?

It's a hormonally compromisd Mandarin. No Wood Duck about it.

 

[FBBird]

I believe this is due to the slight seasonal difference in their breeding cycles- Wood Duck nests earlier apparently. Its only a marginal difference but enough to prevent successful colonisation in UK climate.

Also, Carolina ducklings are slightly smaller at hatching, so are that bit more vulnerable to weather conditions.

 

[Andrew Swales]

It's a hormonally compromisd Mandarin. No Wood Duck about it.

This IS probably the answer. Changes from female to (partially) male plumage is relatively common in Mandarins. This one is well advanced, but there is still something about it which sits rather awkwardly... It happened many times when I was breeding 'ornamental' waterfowl, and of over 30 spp bred we never had it with any other spp. Carolinas do breed much earlier in the year, and the ducklings are much more nervous and generally harder to rear (especially to start to feed) than Mandarins.

 

[TeaLovingDave]

The BTO Bird Atlas 2007-11 treats the Indian Peafowl, Reeves's Pheasant, and Carolina Wood Duck as being established introduced species in the UK, but none of those species have very many records from the UK on eBird (specifically, the Reeves's Pheasant has none).

I seem to recall that the Reeves' introduction represents multiple short-lived populations arising from captive escapes which last only a generation or so before dying off, rather than a constant and established population - and much like the Lady Amherst's Pheasant, I believe the species is currently extinct in the UK.

On a side note, in the UK the Mandarin Duck appears to be one of the handful of non-native introductions which has slipped into the ecosystem with no noticable negative impact - it fills a niche which is otherwise unoccupied, it does not compete with any native species or (as discussed above) hybridise with existing vulnerable species, and even our depauperate native predator populations are able to keep it in check.

 

[FBBird]

This IS probably the answer. Changes from female to (partially) male plumage is relatively common in Mandarins. This one is well advanced, but there is still something about it which sits rather awkwardly... It happened many times when I was breeding 'ornamental' waterfowl, and of over 30 spp bred we never had it with any other spp. Carolinas do breed much earlier in the year, and the ducklings are much more nervous and generally harder to rear (especially to start to feed) than Mandarins.

The slightly incongruous bit is that whacking great crest, nearer the crest of a Mandarin drake in size than that of a female. I've seen this style of crest on an aged drake that didn't colour up properly any more, and suspect it would be the same on a female with atrophied ovary.
I need to check my records, but I'm pretty sure Carolinas take two weeks longer to fledge than Mandarins, which again makes them more vulnerable in a free living setting.

 

[FBBird]

I seem to recall that the Reeves' introduction represents multiple short-lived populations arising from captive escapes which last only a generation or so before dying off, rather than a constant and established population - and much like the Lady Amherst's Pheasant, I believe the species is currently extinct in the UK.

On a side note, in the UK the Mandarin Duck appears to be one of the handful of non-native introductions which has slipped into the ecosystem with no noticable negative impact - it fills a niche which is otherwise unoccupied, it does not compete with any native species or (as discussed above) hybridise with existing vulnerable species, and even our depauperate native predator populations are able to keep it in check.

On the Reeves' Pheasant front, some estates still turn them out for shooting, which would account for fluctuations in numbers seen and reported. The attraction from a shooting point of view is the greater manoeuvrability in the air, facilitated by that long tail. A Game Pheasant goes straight up and keeps going, a Reeves' can do handbrake turns in mid air.

 

[Cassidy Casuar]

On a side note, in the UK the Mandarin Duck appears to be one of the handful of non-native introductions which has slipped into the ecosystem with no noticable negative impact - it fills a niche which is otherwise unoccupied, it does not compete with any native species or (as discussed above) hybridise with existing vulnerable species, and even our depauperate native predator populations are able to keep it in check.

That didn't keep them from being included in the 2015 Field Guide to Invasive Plants & Animals in Britain, though. The book states that Mandarin Ducks compete with other cavity-nesters for nest sites, to my recollection.

 

[FBBird]

That didn't keep them from being included in the 2015 Field Guide to Invasive Plants & Animals in Britain, though. The book states that Mandarin Ducks compete with other cavity-nesters for nest sites, to my recollection.

I'm struggling to think of another cavity nesting animal of a size to compete with Mandarin. They don't occur in the same areas as Goldeneye, and our other hole nesting ducks (Goosander, Red-breasted Merganser and Shelduck) would need significantly bigger cavities. It's probably an unfashionable opinion, but I think Mandarin are a positive addition to our avifauna.

 

[TeaLovingDave]

I'm struggling to think of another cavity nesting animal of a size to compete with Mandarin. They don't occur in the same areas as Goldeneye, and our other hole nesting ducks (Goosander, Red-breasted Merganser and Shelduck) would need significantly bigger cavities. It's probably an unfashionable opinion, but I think Mandarin are a positive addition to our avifauna.

In point of fact, three of the four hole-nesting ducks to which you refer have been part of our breeding avifauna for less time than has the Mandarin Duck - the two Mergus species started to breed in the UK in the late 19th century, and the Goldeneye in the 1970s, all three having previously been winter visitors only.

And as you note, none are found in the same precise ecological niche as the Mandarin Duck.

 

[TinoPup]

My feeling is that this could be a very clever and convincing photo-shop. The head (from a sex-changed or partially eclipsed Mandarin?) feathers on the cape, both at the cheeks and on the nape, do not seem to fit/flow quite right onto the Carolina parts...

I'd be inclined to agree with that. The head doesn't seem to sit right with the body.

It's not a photoshop, it's a real bird. Ran it through software that can detect that stuff just to be sure.

 

[Great Argus]

In point of fact, three of the four hole-nesting ducks to which you refer have been part of our breeding avifauna for less time than has the Mandarin Duck - the two Mergus species started to breed in the UK in the late 19th century, and the Goldeneye in the 1970s, all three having previously been winter visitors only.

And as you note, none are found in the same precise ecological niche as the Mandarin Duck.

That is an interesting fact, so really they weren't competing with anything but maybe the occasional Shelduck. Have there ever been any studies on whether Mandarins oust woodpeckers or other cavity-makers? My guess would be they don't, but an interesting thought. Being as Mandarins are smaller than the mergansers, Shelduck, and Goldeneye, do their old nest holes get used by the larger species later on?

 

[Zoovolunteer]

Our native woodpeckers are much smaller than Mandarin. so there would not be much competition likely. I believe Goldeneye mainly use old Black Woodpeckers holes on mainland Europe - the lack of Black Woodpecker in the UK is probably why they almost entirely use nest boxes in the UK. Shelduck tend to use rabbit burrows more than tree cavities. I am not sure what Mergansers use.

 

[Great Argus]

Our native woodpeckers are much smaller than Mandarin. so there would not be much competition likely. I believe Goldeneye mainly use old Black Woodpeckers holes on mainland Europe - the lack of Black Woodpecker in the UK is probably why they almost entirely use nest boxes in the UK. Shelduck tend to use rabbit burrows more than tree cavities. I am not sure what Mergansers use.

I'd forgotten Black Woodpecker is absent from the British Isles. Great Spotted isn't big enough apparently.

 

[FBBird]

That is an interesting fact, so really they weren't competing with anything but maybe the occasional Shelduck. Have there ever been any studies on whether Mandarins oust woodpeckers or other cavity-makers? My guess would be they don't, but an interesting thought. Being as Mandarins are smaller than the mergansers, Shelduck, and Goldeneye, do their old nest holes get used by the larger species later on?

I've just thought of three potential nest site competitors: Tawny Owl, Stock Dove and Jackdaw. If competition became an issue, extra nest boxes would address it. It's quite likely that the same hole would be used sequentially by more than one species.

 

[Jennings]

Could you post a link to the record, please? It's not showing up on the species map or on the UK species list for All Years.

Lever reports Reeve's Pheasants in six localities across three English counties (Norfolk, Somerset, and Wiltshire) in 2002, eight displaying males at the Stanford Training Area in Norfolk in 2003 and 2004, and displaying males at six sites in 2005. No breeding was recorded on any of these occasions.

(Lever, Christopher, 'The Naturalized Animals of Britain & Ireland', New Holland, London 2009)

 

[Cassidy Casuar]

In Australia, Pacific Rats are apparently very rare, and only definitely exist on Christmas Island, Adele Island (Western Australia), and Norfolk Island. They might also exist on Sunday Island (Western Australia) and Murray Island (Torres Strait).
Ferrets may have populations in Western Australia, southern NSW, Victoria, King Island, and Tasmania, but the existence of established feral ferret populations in Australia has not been confirmed so far (and hopefully it stays that way).
As has previously been discussed on this forum at length, Blackbuck once existed in Cape York and Perth, but are gone now.

For a guide that is meant to be comprehensive (it prominently features several non-established species), West's Guide to Introduced Pest Animals of Australia is missing a lot of birds. Species that really should have been included are the Mallard, Domestic Greylag Goose, Helmeted Guineafowl, Common Pheasant, Feral Turkey, and Indian Peafowl. Others that could have been included are the Ostrich, California Quail, Chukar, Mute Swan, Domestic Swan Goose, Muscovy Duck, Mandarin Duck, Monk Parakeet, etc.

 

[FBBird]

Lever reports Reeve's Pheasants in six localities across three English counties (Norfolk, Somerset, and Wiltshire) in 2002, eight displaying males at the Stanford Training Area in Norfolk in 2003 and 2004, and displaying males at six sites in 2005. No breeding was recorded on any of these occasions.

(Lever, Christopher, 'The Naturalized Animals of Britain & Ireland', New Holland, London 2009)

I photographed a male in the New Forest this summer. Interesting that none of these records refer to hen Reeves'.