Out of the cage

Over the past week, I’ve looked into aspects of parrot conservation, and there seemed to be something of a split between two lines of investigation: parrots threatened in their native range, and parrots causing problems as introduced species. This week I’ll concentrate on the former and then next week, I’ll gather some information on the invasive species issue. As charismatic, intelligent animals, parrots have caught the eye and interest of humans for quite some time, but the emphasis there seems to have been on how having pet parrots and parrot feathers could improve our happiness- we weren’t paying as much attention to the needs of wild populations. Thanks largely to habitat loss and hunting (for live and dead animals), of the 355 living species of parrot, 96 were at high risk of extinction in their native range by 2011 (Legault et al. 2011)- that’s more than 25% of extant species and doesn’t count those already lost. In the Americas by 2001 46 of 145 species were at risk (Milius 2001).

A Moluccan cockatoo who is quite happy to be out of his personal cage

A Moluccan cockatoo who is quite happy to be out of his personal cage

Dwindling wild populations have become more vulnerable to a variety of events. The wild Puerto Rican parrot population, for example, had been reduced to 13 individuals in one location in 1975 (Beissinger et al. 2008)- a huge hurricane hitting in exactly the right (or wrong) spot, a freak fire, a disease outbreak- any of those things could have wiped out the remaining birds. And there are long-term consequences when a population gest that small- inbreeding depression caused by lack of genetic variation can leave animals susceptible to changes in their environment and with decreased reproductive success. 30 years after that low, the Puerto Rican parrot numbered only 30-35 individuals (White et al. 2005), which is an unusually slow rate of growth. When shrinking habitat is added to the equation, recovery can be really challenging. One of the concerns about the two species of parrot found on the island of Dominica is that they will start competing with each other as more and more land is developed for other uses (Christian et al. 1994), and so the question is how to support both populations right now plus protect habitat for the future. In New Zealand, the wild population of orange-fronted parakeets had fallen to about 300 by 2009, partly because of habitat loss, but also due to predation by introduced species such as house cats and rats (Ortiz-Catedral and Brunton 2009b), so conservation planners had to investigate whether some habitats were safer than others for population recovery. Are these smaller populations doomed? Not necessarily- the wild echo parakeet population on Mauritius was down to 8-12 animals in the mid-1980s (Taylor and Parkin 2010), but has been able to rebound to almost 600 in 2012- in fact, starting in 2007, it’s conservation status was down-graded from critically endangered to endangered. Obviously, it’s not out of the woods yet, but it’s definitely a cause for hope.

What can be done to help these smaller populations? From the literature, it appears to boil down to three main things: habitat restoration, reintroduction, and education. As Legault et al. (2011) remarked, most parrots need forests, so habitat conversion is a real problem for these animals. Dominica has worked to create parks that encompass some of the parrots’ range, as well as supporting public education and the development of ecotourism as a means of slowing further habitat loss (Christian et al. 1994; Christian et al. 1996). Researchers in New Zealand have used several predator-free small islands as release sites for endangered parakeet species- this way more habitat is available to the species, and the released populations can acclimate and expand in a safer environment (Ortiz-Catedral and Brunton 2009a; Ortiz-Catedral and Brunton 2009b). (And remember that many reintroduced birds are captive-reared- they don’t always know how to behave around predators- the releases of thick-billed parrots in Arizona recounted in Snyder et al. (1994) are particularly depressing in that respect.) There are now 2 Puerto Rican parrot populations in the wild after a series of releases established a new group in a different part of the island- this will (hopefully) increase genetic variability, but also serves as a buffer in case a natural disaster hits the original group (iucnredlist.org).

So things are not entirely rosy when we look at native parrot populations around the world, but that’s only one side of the story- for next week I’ll look at the other end of the spectrum in those places where parrots are new, and not always wanted, arrivals.

Works cited:

Beissinger, SR, Wunderle, Jr., JM, Meyers, JM, Seather, B-E, and S Engen. 2008. Anatomy of a bottleneck: diagnosing factors limiting the population growth in the Puerto Rican parrot. Ecological Monographs 78: 185-203.

Christian, CS, Potts, TD, Burnett, GW, and TE Lacher, Jr. 1996. Parrot conservation and ecotourism in the Windward Islands. Journal of Biogeography 23: 387-393.

Christian, CS, Zamore, MP, and AE Christian. 1994. Parrot conservation in a small island-nation: case of the Commonwealth of Dominica. Human Ecology 22: 495-504.

Legault, A, Chartendrault, V, Theuerkauf, J, Rouys, S, and N Barre. 2011. Large-scale habitat selection by parrots in New Caledonia. Journal of Ornithology 152: 409-419.

Milius, S. Parrot survey finds poaching but also hope. Science News 159: 343.

Ortiz-Catedral, L and DH Brunton. 2009a. Nesting sites and nesting success of reintroduced reed-crowned parakeets (Cyanoramphus novaezelandiae) on Tiritiri Matangi Island, New Zealand. New Zealand Journal of Zoology 36: 1-10.

Ortiz-Catedral, L and DH Brunton. 2009b. Notes on the diet of the critically endangered orange-fronted parakeet (Cyanoramphus malherbi) on Maud Island. New Zealand Journal of Zoology 36: 385-388.

Snyder, NFR, Koenig, SE, Koschmann, J, Snyder, HA, and TB Johnson. 1994. Thick-billed parrot releases in Arizona. The Condor 96: 845-862.

Taylor, TD and DT Parkin. 2010. Preliminary insights into the level of genetic variation retained in the endangered echo parakeet (Psittacula eques) towards assisting its conservation management. African Zoology 45: 189-194.

White, Jr., TH, Collazo, JA, and FJ Viella. 2005. Survival of captive-reared Puerto Rican parrots released in the Caribbean National Forest. The Condor 107: 424-432.