Individual study: The restoration of the Mauritius kestrel Falco punctatus population
Jones C.G., Heck W., Lewis R.E., Mungroo Y. & Cade T.J. (1995) The restoration of the Mauritius kestrel Falco punctatus population. Ibis, 137, s173-s180
This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.
Control mammalian predators on islands for raptors
A study of an integrated conservation programme for the endangered Mauritius kestrel Falco punctatus from 1973-1994 in montane forest habitat and a captive breeding centre in Black River, Mauritius (Jones et al. 1995) found that trapping and removing nest predators may have significantly increased breeding pair productivity. Two introduced predators (small Indian mongoose Herpestes auropunctatus and feral cat Felis catus) were trapped near some wild nests and at all artificial nestboxes. The authors provide no data on the numbers of predators trapped or experimental data on the effects of their removal.
Remove eggs from wild nests to increase reproductive output
A replicated 1995 study on the Mauritius kestrels Falco punctatus conservation programme (Jones et al. 1995) found that harvesting whole clutches rather than single eggs was more successful in increasing wild pair productivity: 95% of females re-laid within 14 days of clutch removal, but fertility fell rapidly in clutches where eggs were removed as they were laid. Females laid up to 4 clutches/season as a result of harvesting, but clutch fertility decreased to zero by the fourth clutch. Clutch size was an average of 3.4 eggs/clutch for 96 first clutches, compared with 3.3 for 63 second clutches.
Use captive breeding to increase or maintain populations of raptors
A 1995 update (Jones et al. 1995) of the same conservation programme studied in Cade & Jones 1993, found that hand-rearing Mauritius kestrel, Falco punctatus, eggs from birds in captivity was less successful than rearing wild-laid eggs. This study is discussed in more detail in ‘Artificially incubate and hand-rear birds in captivity’.
Release captive-bred individuals into the wild to restore or augment wild populations of raptors
A 1995 update (Jones et al. 1995) of the same conservation programme studied in (6), found that hacking released captive-bred Mauritius kestrels Falco punctatus nestlings significantly contributed to the recovery of the natural population. A total of 331 birds were released into various sites from 1984-1985 and 1993-1994 of which 78% became independent and 61% survived their first winter. Of 208 fledglings hacked (25-34 day old nestlings were put into small groups in a nest box and food was provided while hunting skills were honed), 79% became independent. Most moved out of the release area between 85-100 days; similar to that of natural parent-raised birds. However, only 38% of released first-year females successfully fledged young whereas older females averaged 2 fledglings/nest (from 64% of nests). The remainder of the released captive-bred young were fostered (see ‘Foster eggs or chicks with wild conspecifics’). At the end of the 1993-1994 breeding season, the natural population had recovered to 222-286 birds (containing at least 56 breeding pairs and 40-70 non-breeding birds), from a low of four wild individuals.
Artificially incubate and hand-rear raptors in captivity
A 1995 update (8) of the same conservation programme studied in (Jones et al. 1995), found that hand-rearing young Mauritius kestrels Falco punctatus hatched from harvested eggs was significantly more successful than rearing eggs laid in captivity (96% and 80% hatching rate respectively). Of 292 fertile eggs, 83% were hatched artificially. Some chicks were retained for the captive breeding programme while the rest were released in areas outside the range of the original population (see ‘Release captive-bred individuals into the wild to restore or augment wild populations’).