BRITISH GUYANA BIRDS EGGS. 121 
being very soft. Sometimes they build in other places. 
The egg sent was taken, along with two others, out of 
an old cassava press, a hollow tube of basket work, which 
had been thrown into a tree. 
They lay three eggs. 
The egg — 26 mm. by 20 mm. — is white. 
They hatch in May and June. — One egg (N°. 34). 
The egg of this bird resembles the egg of the wood- 
pecker, not only by being white but also by having the 
same hard-looking white gloss. 
14. Rosthramus sociabilis (Vieill). 
Cricketa Hawk. 
They build a flat nest of sticks, in colonies, on moder- 
ately high trees in the interior about the head-waters of 
the creeks. 
They lay three eggs. 
The egg — 42 mm. by 33 mm. — is greenish white, 
blotched and spotted with dark brown, or light brown 
marks, no two eggs being marked alike, some have very 
few marks while others are so covered that the ground 
colour of the egg is hidden. 
They hatch in April and May. — Two eggs (N°. 39). 
After the breeding season these hawks separate and scatter 
all over the colony where there is fresh, still water, where 
they catch the fresh water-snail, called cricketa, on which 
they live. They lift this snail out from among the water- 
plants by their feet, as other hawks lift birds, but when 
they get clear of the water-plants, they, while on the 
wing, take the shell from their feet and carry it in their 
bill to one particular dry branch where they eat the 
snail: below this branch one can find a pile of empty shells. 
15. Cathartes aura (L.). 
Red-headed Carrion Crow. 
The nests of these birds are very hard to find although 
Notes from the Leyden Museum, Vol. XV. 
