Saturday, 30 August 2014

Saving the Fig Parrot

Brisbane has some beautiful coastal wetlands.  In large cities like Brisbane, the coastal wetlands are usually the last native ecosystems present that would be similar to how they were when the early settlers arrived.  The bush and rainforest have been transformed by weeds and have become an alien vegetation that is dominated by a handful of adaptable and aggressive species such as noisy minors that exclude other birds and animals.  Brisbane was a biodiversity hot spot but much has been lost.  Mangroves forests and salt pans which were once the poorest habitats for fauna have now become one of the richest as they are relatively immune to degradation.  Mangroves and the small islands of terrestrial forest they contain may even be the last habitat of some species.

Perhaps the rarest and most endangered bird in South East Queensland is Coxen’s Fig Parrot (Cyclopsitta diophthalma coxeni).  There are an estimated 100 individuals left but no one really knows as they are a cryptic species.  The small green parrots feed quietly on native rainforest figs and being the size and shape of fig leaves, they are very hard to see so targeted searches for this species usually fail to find any.  To save the species, the QLD and NSW State Governments want to start a captive breeding program, but nobody can find an occupied nest.  Stock for breeding programs is normally taken from wild nests.  I suppose that this would make my discovery of some possible old nesting hollows in a mangrove tree a significant find.

Cyclopsitta diophthalma coxeni
Possible old fig parrot nest holes in a mangrove beside the board walk at Nudgee Beach
A lizard in a stag beetle hole in the same tree.  The stag beetles may make pilot holes for the parrots.
Fig parrots make their own hollows.  Over about a month, they chew their way into a rotting branch.  Some hollows are about 60 cm deep which I discovered by finding fallen nest branches which split open when they landed.  If you find a fallen nest or any nest, be sure to report it to the national parks service.

Cyclopsitta diophthalma macleayana
Fig parrot in Cairns starting to tunnel - 17 July 2014.
fig parrot at nesting hole entrance
Stopping for a look around.
Cyclopsitta diophthalma macleayana
30 August, been sleeping in the hole for while now, but when there is a noise, the parrot comes to the entrance for a look (flash photo taken just after dark).
Cyclopsitta diophthalma macleayana
Female fig parrot begging for food from its mate.
Cyclopsitta diophthalma macleayana
Male fig parrot about to feed the female.
There is a species recovery plan for this species but it does not appear to address the nesting requirements for this species.  My knowledge of the subject comes from observing another subspecies of fig parrot, the red browed fig parrot (Cyclopsitta diophthalma macleayana) which is still common in Far North Queensland.  Fig parrots need rotting branches between 10 and 25 cm in diameter where the sapwood softens without the branch falling.   Live timber is too hard and in many cases would have unpleasant sap.  In nesting branches, often the sapwood rots away completely and the dead branch becomes an empty tube of bark when the parrot scrapes out the contents.  The favoured species are fig trees (F. drupacea) but I have seen nests in beach almonds (Terminalia arenicola).  I even have a nest near my house in a rainforest tree with one of the hardest scientific name I know of (Blepharocareya involucrigera).  Many of the nesting trees are in parks.  Twenty years ago, I would only see fig parrots flying in small groups high in the sky.  In only a few years, the fig parrots have moved into town.  I suspect many/most urban nests are lost to tree loppers who are called in to remove sick trees and dead branches.   If we can find places where trees can be allowed to old and decrepit, then every park fig in Brisbane City could one day be visited by this species.  Figs branches tend to rot until they become as light as foam before falling and if dead branches of suitable diameter were cut off a bit more than half a metre from living timber, the safety hazard from falling branches would be very small.  In fact many of the local nests around Cairns are in the stubs of branches that were trimmed by the city council.   Any branch with a gnawed hole or a gnawed test pit should be off-limits to tree trimmers.  The birds tend to chew out test pits until they find timber that just right.

Although I did find nest hollows in the mangroves, I do not believe that in general mangroves are suitable habitat.  Mangroves have high populations of rats which predate crabs and which would prey on parrot chicks as well.
Cyclopsitta diophthalma macleayana
Red browed fig parrot feeding on Ficus racemosa on an isolated tree on a sand ridge in the mangroves.
I suspect that another serious oversight of the recovery plan is that it does not address the food supply of the fig parrots.  Fig parrots eat green figs and not ripe figs. The northern fig parrots feed very heavily on Ficus racemosa and to a lesser extent on F. drupacea, both of which are native to Brisbane but which are rarely planted.  These figs are deciduous and drop very heavy crops of fruit a number of times a year so are not ideal park trees.   Planting these species around the margins of parks, particularly on the edges of the mangroves creeks and other places where people don’t typically venture might be a way of boosting food resources.  Fig parrots are highly mobile and isolated trees make up most of their food supply.  Another undocumented food is Melaleuca viridiflora flower buds.

Fig parrots feed for days to weeks on a single tree until fruiting stops and they return as soon as fruiting begins again, so isolated urban trees are likely to be extremely important to this species.  The species recovery plans should include the establishment a network of isolated trees which can fee the birds year round.  All the photos above were planted trees.  I planted them.

Tabbil-ban dhagun boardwalk at Boondall Wetlands
The 1.5 km long km board walk at Nudgee Beach is just across from Brisbane Airport - something to do before you catch a plane. 

Further Reading:
Coxens fig parrot Species Recovery Plan

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