Bl2 Mr. E. Gibson on the Ornithology of [Ibis, 



A young male in my collection (obtained by Claude 

 Grant) bas the following notes on the label : — "• Iris clear 

 hazel-brown. Bill black. Cere, gape, orbits greenish 

 yellow. Legs and toes lemon-colour. Claws black." 



307. Rostrhamus sociabilis Vieill. Sociable Marsh-Hawk. 



Adult. Iris ruby-colour. Gape and bare parts round 

 eye bright orange-red. Beak and claws jet-black. Legs 

 and feet bright orange-red. 



Yotmg. As above, except gape and bare parts yellow. 

 Legs and feet orange. 



Since I described the habits of this handsome and in- 

 teresting species in 1879, my diary furnishes me with but 

 little further information. It is fairly regular in its 

 migration, arriving in this district about the middle of 

 September and leaving midway in March, though I liave 

 known it to be abundant at the end of August and to dis- 

 appear at the end of February, in spite of overflovviug 

 swamps. Whence it proceeds and wliere it goes — particu- 

 larly during such an e{)Och as that of our four years' 

 drought — I do not know ; but in sucli floods as that of 

 1899-90, and the still greater one of 1913-15, the numbers 

 all over the country (during the usual season) were extra- 

 ordinary. Not only were they in evidence in their favourite 

 swamps and all over the inundated country-side, but Hying 

 over the Yngleses head-station and woods (one individual 

 actually working through the dark recesses of the latter like 

 an Owl), and occasion;dly even alighting on a Eucalyptus or 

 Tala tree (again a most unusual procedure). As the shallows 

 dried up, and tlie waters withdrew into their normal swamps, 

 it was wonderful to see the accumulation of water-snail shells 

 {Ampullaria caaaliculata Lamarck), the sole food of this 

 Hawk, at the foot of each and every isolated Durasnillo or 

 clump of the same trees, or posts of a fence passing through 

 ornear a swamp. •' BucketsfuT' would be the only adequate 

 description. One such heap at the base of a post numbered 

 over 1500, and all the posts on the line of fence, for a con- 

 siderable distance, had. an approximate quantity ! 



