Adult Mauritius Kestrel; Photo: A. Roberto-Charron

The Mauritius Kestrel was once the rarest bird in the world. The recovery of this species is one of the most inspiring conservation successes, and its story fills me with hope and optimism.

The Mauritius Kestrel is a compact falcon with fierce, piercing eyes. It resembles the European or American Falcon, but is unmistakable. The Mauritius Kestrel has a cinnamon-brown back, white breast, and has an overall softer and more rounded silhouette when contrasted with its European or American counterparts.

Three Mauritius Kestrel chicks in a nest box; Photo: A.Roberto-Charron

The Mauritius Kestrel was at one time extinct in the wild, with the population reaching a low of 4 individuals in 1974, consisting of 3 breeding females and 1 breeding male. Its population decline was primarily due to loss of habitat and prevalent use of pesticides such as DDT. The effects of DDT have been widely reported, and were publicized in the book ‘Silent Spring’ by Rachel Carson. In raptor species, DDT causes the thinning of eggshells, which are crushed under the weight of the female during incubation, ultimately killing the embryo. Globally, DDT has had a very detrimental effect on numerous bird of prey species.

Kate Downer, a Mauritius Kestrel biologist, feeding chicks in a nest box; Photo: A.Roberto-Charron

Amazingly, through intensive conservation efforts, the Mauritius Kestrel has made an incredible recovery. In fact, the species now has a population of several hundred! Without captive breeding and intensive management over the last 45 years, this species surely would be extinct.

Having learned about the Mauritius Kestrel through my studies, I was elated at the opportunity to see one in Mauritius. When I saw my first Mauritius Kestrel I felt very emotional. As I watched this little falcon fly through the woods, agile and graceful, the significance of its recovery made a powerful impression. Not only did this little falcon make it back from the brink of extinction, but it had become a symbol for me of optimism and possibility. Through organized conservation efforts, species recovery really is achievable.

Kate Downes, a Mauritius Kestrel biologist, monitoring a nest box; Photo: A.Roberto-Charron

That being said, work is still ongoing to increase and stabilize population numbers of the Mauritius Kestrel. As populations in the eastern portion of Mauritius are faring better than populations in the west, the work this season was focused on introducing birds from the east to the west. Eggs were collected from breeding pairs in the east coast population, hatched in incubators, hand-reared and placed in new unoccupied nest boxes in the Black River Gorges National Park. These boxes were tended to by biologists, who provided food for the chicks until they were ready to be self-sufficient.

I was fortunate enough to join the kestrel biologists on two separate occasions to see and feed the chicks at two different stages; once when the chicks were quite young, and once when they had already fledged and were coming to be hand-fed. Both experiences were extremely memorable.

Katiana Saleiko, a Mauritius Kestrel biologist, feeding a chick; Photo: L. A’Bear

During my first weekend assisting on the project, I accompanied one of the kestrel biologists to prepare the food for the kestrel chicks. This involved preparing thawed mice by removing their fur and digestive track. Once the food was prepared we visited the nest box sites. The nest boxes were set up in trees approximately 6 meters high in a natural area. Small rubber bricks were affixed to the trunk of the tree to allow us to climb the tree to access the nest box. The first time I tried climbing a tree to reach the nest box, I lost my nerve after only a few meters. However, when I heard the chicks inside begging, it spurred me on. Through the guidance of the biologist, I climbed to the nest box and opened it. The chicks inside were eagerly waiting to be fed, clamouring over one another and loudly begging for food. Once a chick was fed a large mouse that was equivalent to half its body size, it would run to the back of the box to tear it apart and eat it with fervour. It was a wonderful weekend spent climbing trees, feeding chicks and enjoying beautiful vistas.

Amélie Roberto-Charron feeding a Mauritius Kestrel chick; ; Photo: L. A’Bear

The next time I assisted with the kestrel feeds, the chicks were almost grown and had fledged from the nest boxes. This time, rather than waiting in the nest boxes to be fed, they responded to the blow of a whistle and came to be hand-fed a whole mouse. The chicks that I had first seen so defenceless and small were now fierce falcons that were effortlessly flitting around impatiently waiting to be fed. In turn, the chicks would swoop down to collect mice from our outstretched hands.

It was fantastic to see the progression of these chicks and to see them nearly independent. Being involved in the important on the ground conservation program helping this emblematic and endangered falcon is a memory I won’t soon forget. Through dedication and hard work of several dedicated biologists success stories like that of the Mauritius Kestrel are possible.