This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
The great recovery from almost-extinction of the Mauritius kestrel is regarded as one of the most spectacular raptor conservation programs in the world. Better known as the “Crécerelle de Maurice” in its native island of Mauritius, the Mauritius kestrel had a population of only four individuals in the wild in 1974. Today, the estimate of its population is around 800-1000 individuals [1]. What did it take for such a conservation success story to happen in Mauritius—an island infamously known for the ill-fated Dodo—and what lessons can the world learn from this story?
Being the only falcon species living on the island, the Mauritius kestrel is easily recognized in the wildlife of Mauritius. Measuring a small 20-26 cm in length, it features black blotching on its otherwise white underpants. Its wings, chestnut in colour with black crescent markings, make the bird appear stunningly imperial when seen in the blue Mauritian sky.
The Mauritius kestrel evolved some two million years ago in the Gelasian. Populations of the Indian Ocean kestrels settled on the then isolated islands of Madagascar, Seychelles, Réunion and Mauritius and eventually evolved each into their own species, one of which was the Mauritius kestrel [2].
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In those times before the presence of human settlements on the island, the falcon was living throughout Mauritius’s coastal and mountain areas. However, once the island received its first human settlements around 400 years ago, the falcon was severely harmed. A mere 300 years after the colonization of Mauritius by the Dutch (a rule which preceded that of the French and English), the Mauritius kestrel would ultimately be restricted to only four individuals which included only one breeding female.
How did such a catastrophe happen? The Dutch, most notorious for the mass-killing and eventual extinction of the Dodo, severely deforested Mauritius. Further large-scale forest clearances were later ordered by the succeeding French and English. After four centuries of human settlement, only two percent of the native forests remained. But the Mauritius kestrel did not only have to deal with a reduction in its habitat. Invasive animals like cats, mongooses, monkeys and rats, introduced by man, began to populate the island. The number of predators became too much for the Mauritius kestrel to bear as eggs, young ones and even adults all became prey. By that time, only a few hundred pairs remained in the wild and they were confined to the least affected parts of the island, where the last of the native forests remained: the mountain areas [3].
As though this struggle was not enough, the Mauritius kestrel’s misfortunes took a turn for the worst in the 1950’s and 1960’s when a malaria epidemic ravaged the human population. In the fight to eradicate the disease, dichlorodiphenyltrichloroethane, commonly known as DDT, was used as pesticide. DDT, toxic to a wide range of animals—the Mauritius kestrel being no exception—nearly proved to be the coup de grace.
This grim state of affairs inspired a conservation effort whose goal—to rescue the Mauritius kestrel from extinction—was thought unthinkable. Among the detractors of the project was British environmentalist Norman Myers. In 1979, Myers wrote: "We might abandon the Mauritius kestrel to its all-but inevitable fate, and utilize the funds to proffer stronger support for any of the hundreds of threatened bird species that are more likely to survive." A few others believed in the project however, as was the case of well-known conservationist and writer, Gerald Durrell.
Remarkably, by 1994, less that 20 years after the start of the conservation project, a free-living population of the Mauritius kestrel has been attained [4]. That same year, the International Union for the Conservation of Nature (IUCN) promoted the species from "Critically Endangered" to "Endangered." Six years later, in 2000, the species’s status was again lifted, this time to "Vulnerable."
According to Dr. Nicolas Zuel, Fauna manager of the Mauritian Wildlife Foundation, the great success of the conservation program was due to the conservation approach of the endeavor and the shear effort and dedication of the conservationists of the time.
The approach the conservation programme pursued was revolutionary for its time. While the norm was to take more of a global approach, putting much emphasis on a species’s habitat, the Mauritius kestrel conservation program instead focused primarily on increasing the population of the species itself.
"Some people," says Dr. Zuel, "suggested we do habitat restoration but that would have been too huge a task. Instead, a species approach was adopted that included new methods. Lots of it was monitoring and studying the species."
With such an approach, it was the captive breeding aspect of the programme that was essential. For the first time, restoring a species’s habitat was not the major focus of effort.
The program included a number of groundbreaking conservation techniques, such as cross fostering, hand rearing and release of captive-bred and captive-reared birds as well as artificial incubation, provision of nestboxes and continued management in the wild [5]. Captive kestrels were fed on mice and small chicks and a few years later, between 1981 and 1986, as many as 13 birds, thrice as many as had been reported in 1974, had been recovered. By the end of the 1986-1987 breading season, these birds had reared more than 30 new ones.
Meanwhile, eggs and nestlings were being removed from nests in the wild and artificially incubated. The young ones were then made available to be released in the wild. Release of captive-bred and captive-reared birds in the remaining endemic forests of Mauritius proved a significant success. More than 75 percent of the birds released in the wild became independent. Furthermore, they were seen to have a high mating rate [6].
Although the conservation techniques employed in the programme were not used in other countries, they were successfully put in practice in conservation projects for other Mauritian birds.
"We used the techniques locally with our native birds namely the Echo parakeet, the Pink Pigeon and the Mauritius fody. They have helped to increase the populations of all these bird species. The techniques were indeed very successful," points out Dr. Zuel.
Since the conservation program, the population of the Mauritius kestrel has continued to increase steadily with an estimate of 800-1,000 individuals presently living in the endemic forests of Mauritius. Active management of the kestrels is not done any more but the population of the species is constantly monitored.
The status of the Mauritius kestrel though is likely to remain "Vulnerable." Due to the relatively small population of the species, the Mauritius kestrel is perpetually at risk. Indeed, chance events like tropical cyclones—not uncommon in the tropical region of Mauritius—may abruptly annihilate the entire population.
Still, this shouldn't gloom the success of the conservation effort that brought the Mauritius kestrel back from the dead. The dedicated conservation approach and techniques that were put into practice bore their fruit: preventing a species that we had led to quasi-extinction from disappearing from the face of the earth forever.
References:
[1] BirdLife International (2008) ‘Falco punctatus’ IUCN 2009: IUCN Red List of Threatened Species [Online], Available: http://www.iucnredlist.org/details/144551/0
[2] Groombridge, J. J., Jones, C.G., Bayes, M.K., van Zyl, A. J., Carrillo, J., Nichols, R. A. and Bruford, M.W. (2002) ‘A molecular phylogeny of African kestrels with reference to divergence across the Indian Ocean’ Molecular Phylogenetics and Evolution, vol. 25, no. 2, October, pp. 267-277.
[3] Mauritius Wildlife Foundation (2008) ‘Mauritius Kestrel’ Mauritius Wildlife Foundation: Annual Report 2007/08, pp. 9.
[4] Jones, C. G., Heck, W., Lewis, R. E., Mungroo, Y., Slade, G. and Cade, T. (1994) ‘The restoration of the Mauritius Kestrel Falco punctatus population’ The International Journal of Avian Science, vol. 137, no. 1, pp. 173-180.
[5] Temple, S. A. (1986) ‘Recovery of the endangered Mauritius Kestrel from an extreme population bottleneck’ The Auk, vol. 103, no. 3, July, pp. 632-633.
[6] Nicoll, M.A.C., Jones, C. G. and Norris, K. (2004) ‘Comparison of survival rates of captive-reared and wild-bred Mauritius kestrels (Falco punctatus) in a re-introduced population’ Biological Conservation, vol. 118, pp. 539–548
Image credits: Photo 1: Mauritius Kestrel (credit: Jjargoud from Wikipedia), Photo 2: Mauritius Kestrel (credit: Bashir Cassimally).
About the Author: Khalil A. Cassimally is a science student by day and science blogger and blog manager at Nature Education by night. He writes about the science that gets him all excited. He also tweets as @notscientific.
The views expressed are those of the author and are not necessarily those of Scientific American.