Jungle fowl

[Chlidonias]

I won't try and dispute anything from the first part of your post -- you're obviously well-acquainted with the history of Gallus -- but this part of your post...

As the Green Junglefowl has such unusual ecological requirements it's highly unlikely that it presents a serious threat to endemic rail. The preferred diet of Gallus varius are crustaceans uncovered in sand, organisms trapped in litoral pools during the low tide, shore line detritus and the fresh green seeds and buds of understory plants. They also forage on decaying fruit.

.....is a pretty good description of the feeding habits of insular forms of banded rail. They are literally in direct competition. It is irrelevant if the junglefowl on the islands are pure or hybrid, they need to be removed.

 

[mihos]

Let's revisit Darwin's finches for a moment. Island adapted species are often extreme ecological specialists. There are more than one species of rail present and any number of Ardeidae-each bird has its own special adaptations -foraging on organisms perfectly dispatched and ingested with the least expenditure of energy -consequent of bill shapes and foraging behaviors, hours of activity, hours of respite- -islands can be hotspots of endemism because of the tendency for its inhabitants to become extreme ecological specialists. They're not delicate - quite the opposite- they're resilient-

We're quickly adopting postions for or against the survival of Cocos Junglefowl- when we might be better served discussing endemism and island biogeography. Islands attract pioneers- island hopping species are sometimes introduced to islands in efforts to conserve them. The green junglefowl is an island hopping species adapted to survive on oceanic islands. It didn't reach the Cocos by flying. That can't be debated. Wild populations of Red Junglefowl- introduced by early seafarers- on islands across the Pacific and Oceania are/were cohabitants with terrestrial rails. Many of these rails are endemic- and unfortunately many species are extinct due to the introduction of rats and pigs. But it's unlikely wild Junglefowl are serious competitors- Their life histories don't overlap closely. Rails are generally active at hours the junglefowl is not. The rails specialize on certain invertebrates, mollusks and shoots of vegetation, green junglefowl are not adapted for. And rails enjoy eating the eggs and chicks of other terrestrial birds. While rails are omnivores- compared with junglefowl-are obligatory predators. The organisms preferred by rails are in an arms race with their prey. this arms race takes place in the densest vegetation- often marshy vegetation- and during hours when aquatic lifeforms are most visible /active. The junglefowl is never going to compete with the rail in its preferred- in its optimal habitat and neither is the rail competition for the junglefowl.

Rails have such distinctive morphological features-that make them perfectly adapted for life on remote islands- together with other species- a diversity of species- Diversification is the key to life-

The natural history of both species is worthy of serious investigation by objective researchers and that island biogeography - that Alfred Wallace are revisited- and utilised as more important reference for conservationists.

 

[Chlidonias]

Let's revisit Darwin's finches for a moment. Island adapted species are often extreme ecological specialists. There are more than one species of rail present and any number of Ardeidae-each bird has its own special adaptations -foraging on organisms perfectly dispatched and ingested with the least expenditure of energy -consequent of bill shapes and foraging behaviors, hours of activity, hours of respite- -islands can be hotspots of endemism because of the tendency for its inhabitants to become extreme ecological specialists. They're not delicate - quite the opposite- they're resilient-

I'm not quite sure of the relevance of this passage. We aren't talking about insular life in general, we are talking about one particular species on one particular island group: banded rails are in no way comparable to Galapagos finches. On the Cocos (Keeling) Islands there are exactly two species of rails established as breeders, the banded rail and the white-breasted waterhen, which have exclusive life-styles. The only established Ardeidae are nankeen night herons and reef herons, also both exclusive to the life-styles of both of the rails. All of these are widespread species in the Pacific area, of which only one (the banded rail) has an endemic subspecies on the Cocos (Keeling) Islands.

Specialist insular species are not resilient....if that were the case there would not be so many extinct specialist insular species. When generalist species are introduced by man, the specialist species are forced out. In other words specialist species do very well when their ecosystem is intact, but fare badly when their ecosystem is corrupted.

As it happens, banded rails are not specialists in any way, they are generalists. The junglefowl are not the only threat to their survival on the islands, but they are one of them (i.e. the rails are not endangered solely because the junglefowl were introduced, but junglefowl are one of the combatable factors of the rails' endangerment).

We're quickly adopting postions for or against the survival of Cocos Junglefowl- when we might be better served discussing endemism and island biogeography.

that is what the thread is about. The banded rail subspecies of the Cocos (Keeling) Islands is endemic to those islands, while the junglefowl (of both species) are introduced and compete for the same resources. The junglefowl are one of the manageable threats to the endemic bird.

Islands attract pioneers- island hopping species are sometimes introduced to islands in efforts to conserve them. The green junglefowl is an island hopping species adapted to survive on oceanic islands. It didn't reach the Cocos by flying. That can't be debated.

again, I'm not sure what you're saying here: green junglefowl live on islands in the Indonesian archipelago, and therefore introducing them to oceanic islands where they don't belong is acceptable for that reason, and they should remain there even if they have been shown to be a threat to the endemic life-forms of that island?

Wild populations of Red Junglefowl- introduced by early seafarers- on islands across the Pacific and Oceania are/were cohabitants with terrestrial rails. Many of these rails are endemic- and unfortunately many species are extinct due to the introduction of rats and pigs. But it's unlikely wild Junglefowl are serious competitors- Their life histories don't overlap closely. Rails are generally active at hours the junglefowl is not. The rails specialize on certain invertebrates, mollusks and shoots of vegetation, green junglefowl are not adapted for. And rails enjoy eating the eggs and chicks of other terrestrial birds. While rails are omnivores- compared with junglefowl-are obligatory predators. The organisms preferred by rails are in an arms race with their prey. this arms race takes place in the densest vegetation- often marshy vegetation- and during hours when aquatic lifeforms are most visible /active. The junglefowl is never going to compete with the rail in its preferred- in its optimal habitat and neither is the rail competition for the junglefowl.

again, you are speaking in extremely general terms when the topic at hand is solely about junglefowl/banded rails on the Cocos (Keeling) Islands. If you were going to talk generally you should have also mentioned that diseases introduced with domestic fowl and other gamebirds are generally accepted as being the cause or probable cause of extinction or endangerment for a number of island birds, including the New Zealand quail (extinct) and weka (endangered). But introduced disease is apparently not a factor on the Cocos (Keeling) Islands, and thus is of no more relevance than what the factors are at play on other island groups. Your last comments are a nonsense with regards to the life-style of banded rails: they are cathemeral generalists, not (if I am reading you right) marsh-dwelling nocturnal specialists. The fact is they feed on the same food items that junglefowl take, and during the same periods (as well as at night).

Rails have such distinctive morphological features-that make them perfectly adapted for life on remote islands- together with other species- a diversity of species- Diversification is the key to life-

The natural history of both species is worthy of serious investigation by objective researchers and that island biogeography - that Alfred Wallace are revisited- and utilised as more important reference for conservationists.

and if I'm reading this right, you are basically saying that introducing foreign species to insular ecosystems is a good thing? Because it increases the biodiversity? I think island biogeographers might have different ideas about what the outcome of that might be.....





Just some additional information for specifics: the banded rail subspecies found in these islands is now probably confined solely to North Keeling Island which is only 1.2 km² in size. It has been eliminated from all the other islands in the group through a combination of habitat destruction (land clearance) and introduced predators (rats and cats in particular). Competition with junglefowl has also been proven to be a factor. Yellow crazy ants are another major threat now (as is also the case on Christmas Island for the endemic land crabs: nasty things those ants!). Clearing the other islands of introduced species (e.g. rats, cats, junglefowl) will enable rails to be reintroduced there for an increase in the overall population.

 

[mihos]

It's a complex issue to be certain. I do think that parameters of the topic are unnecessarily
narrow and defined by authors with certain prejudices. Here's a paper that deserves a careful read. Presuppositions about an introduced predatory species could not be substantiated. Indeed, it would appear that the cat may be an important predator of the worst threat- the two species of rat. Extermination of these rodents must surely take precedence over the extirpation of an introduced species that happens to be highly vulnerable in its native range.

http://www.sil.si.edu/digitalcollections/atollresearchbulletin/issues/00505.pdf

 

[Chlidonias]

It's a complex issue to be certain. I do think that parameters of the topic are unnecessarily
narrow and defined by authors with certain prejudices. Here's a paper that deserves a careful read. Presuppositions about an introduced predatory species could not be substantiated. Indeed, it would appear that the cat may be an important predator of the worst threat- the two species of rat. Extermination of these rodents must surely take precedence over the extirpation of an introduced species that happens to be highly vulnerable in its native range.

http://www.sil.si.edu/digitalcollections/atollresearchbulletin/issues/00505.pdf

control of introduced mammals in particular is always a balancing act. Most places that have problems with predatory animals have rats and cats as at least two of the components. Trap out the cats and the numbers of rats increase accordingly because they are not being killed by cats; but conversely if the rats are trapped out then the amount of predation upon other animals (e.g. birds) increases because the cats have no rodent prey.

Rats can actually be fairly readily eliminated on islands via the use of poisoning such as 1080 (mentioned in the article), although the problem they discussed was the removal of baits by crabs which isn't a factor on most islands that have been cleared of rats!! Certainly you'd need some clever thinking to get around that one!

Cats can also be removed via the use of poisoning (1080 in meat baits are commonly used in Australia for carnivorous pests such as foxes and cats) or by old-fashioned trapping and shooting (the way it is done in NZ because we don't use meat baits; our 1080 is used in pellet form for herbivores such as possums).

The problem, should the rats and cats be eliminated, is that there would be constant threat of re-invasion (mainly of rats) via ships. Bait stations would need to be set up and maintained to try and prevent this.

Because the rails are now confined to one island, there is actually little risk in a combined cat+rat elimination programme for the other islands (the birds on the other atolls are primarily widespread seabirds and will not be affected in the long-term by any short-term increase in rat/cat numbers should either occur before total elimination).

But there is little point in just leaving junglefowl on islands intended for rail re-introductions when they could impede the survival of the rails. They may be the lesser of the problems but they can still be removed to the benefit of the ecosystem of the islands.

 

[mihos]

What's the likelihood of the birds actually being eliminated on all islands? Is there word of when this initiative might take place and is there potential for capture and rerelease of the birds on another island in their native range? Would Australian Zoos and private aviculturists be feasible?