Caption
Balls formed in and around nests of guanay cormorants (Phalacrocorax bougainvilliiorum) as they walk over moist ground and coat loose stones, or even eggs, with guano. Each of the balls usually has a stone (or occaionally an egg) inside. Punta San Juan, (Reserva Nacional de Islas, Islotes y Puntas Guaneras) Peru.
Availability
Only inBelgium, Canada, France, Luxembourg, Switzerland