41S PERCY SLADEN TRUST EXPEDITION 



return singly, and each bird reaches its nest by partly flying and partly running over the 

 flat top of the tree, the result being that most of the eggs in the path of a returning bird 

 are either broken or rolled off the nest into the water below. Out of eighteen eggs 

 counted when the birds were away, but two remained whole after they had all returned. 

 If this manoeuvre is often repeated, it is difficult to understand how the birds are as 

 numerous as they are. 



Next perhaps to the ibis in point of interest is a small rail, Dryolirnnas aldahranus, 

 closely allied to D. cuvieri of Madagascar and Mauritius. It is a pretty bird, olive green 

 above, and underneath a rich chestnut with white chin and neck. It is generally distri- 

 buted over the atoll, though it is scarce on Picard, and has apparently been exterminated 

 in the neighbourhood of Takamaka by the cats. It is extremely tame, and at Esprit 

 Island would often come inside the hut, where several attempts were made to photograph it, 

 but owing to its preference for dark places and its quick jerky movements, these always 

 resulted in failure. Its most marked peculiarity is the astounding variety of noises which 

 it can utter, the most curious being like a stroke on a native drum, which is usually 

 followed by a long whistle, often an exact reproduction of a curlew's call : when the bird 

 is excited it makes such a remarkable series of grunts and shrieks that Nicoll [Three 

 Voyages of a Naturalist) has likened them to the noise produced by a drove of pigs. 

 All these cries are produced with the head pointing upwards and the throat much 

 distended, and are very loud for the size of the bird, which is smaller than that of 

 a water-rail (R. aquaticus). Flight is but rarely indulged in, though the birds can flutter 

 along, and are certainly not flightless as stated by Abbott. They are the only bird which 

 inhabits the dense Pemphis bush, and are often to be found at low tide in the rocky pits, 

 which abound in the " champignon." Their food consists of insects and small crustaceans. 

 No nest was found or young birds seen, and it is probable that they do not breed until 

 February or March. 



Another interesting bird is the Aldabra cuckoo (Centropus aldahranus), which 

 resembles the Madagascar C. toulou and is known locally as " toulouse." It inhabits 

 chiefly the open country in the south-east of Main and Picard Islands. In character 

 it is very terrestrial and is often found on the rock underneath the bushes, though, when 

 disturbed, it climbs about among the trees and shrubs with actions like those of a parrot. 

 Towards sunset the male flies to the top of a tree and utters repeatedly a peculiar and 

 melodious call consisting of a series of notes (semitones) descending the scale for three or 

 four tones : the birds do not all have the same range of notes, and it was not uncommon 

 for two birds to call together producing a series of chords down the scale. The cry carries 

 a long distance and can be heard at least a mile away : it forms one of the lasting 

 impressions in connection with evening on Aldabra. Only one nest was seen, and this 

 consisted of a large mass of sticks low down in a bush : it had no eggs in it. 



Of doves there are two: — Alectroccenas aldahranus or "pigeon hollandais" and 

 Turtur aldahranus {saturatus ?). The latter, which resembles a small T. picturatus, was 

 not uncommon near the settlement and also at Michel Island, while the former inhabits 

 the less frequented parts of the atoll and was common at Takamaka. Both birds seem to 

 have a definite time of flight in the evening. 



