Hi everybody! I'm writing to share a curiosity about working at-sea: we often see more than just seabirds out on the open ocean. There are many reports from captains and crew about passerine and coastal birds that are swept out to sea on strong winds and land on passing vessels over one hundred miles from the coast. Some captains have cages and bird food on board, and if some passerine appears, they help the little bird to recover, bring it to land, and release it. Since the first time I saw a land bird at sea, on board the oceanographic vessel Atlantico Sul, from Universidade Federal do Rio Grande-FURG, I have taken note of these bizarre encounters. Over seven at-sea trips on board oceanographic and fishing vessels, from 2009 to today, I have recorded 18 different species of land birds, adding up to 48 individuals. Of these, 20 were cattle egrets, in general flying high, in small flocks. Others include flycatchers, seed-eaters, finches, blackbirds, meadowlarks, thrushes, pigeons, swallows and nightjars.
Below, a female Saffron finch sits out rought weather on some deck netting.
Once, in October 2009, during a scientific survey aboard the oceanographic vessel Atlantico Sul, I saw 17 individuals of nine different species of land bird all on the same day. All these birds landed on the ship, clearly exhausted, during bad weather with strong offshore winds. Seven of the passerines belonged to three species of temperate-tropical migrant flycatchers, which breed in temperate zones of South America during the spring-summer and migrate to warmer, humid regions during autumn. These birds, flying high during their migration could be more exposed to strong winds, and October coincides with the arrival of these species to the temperate region. During the day I found the birds I thought: If in this afternoon 17 individuals reached the vessel I was on, 110 miles from the coast, how many birds must have been blown out to sea?
Below, a Tropical kingbird clutches to a support cable.
The species most frequently observed is the Cattle Egrets, which is the only one I’ve seen flying high at-sea. These species are originally from Africa, but over the last century they have colonized all continents (except the Antarctica). The Cattle Egret are strongly associated with large mammals, because they feed on terrestrial arthropods and small vertebrates that are flushed out by the large herbivores as they wander and graze. After the extensive introduction of cattle grazing worldwide, all continents became a suitable place for the Cattle Egret, and these at-sea encounters corroborates the amazing dispersive capability of this species.
Below, cattle egrets fly high above the vessel far out to sea.
Seeing so many land species at-sea, blown off course by strong winds, makes me appreciate the phenomenon of dispersal including the transfer of energy from land to sea; the process of colonization of oceanic islands; and the possible contribution of ships and others vessels to the range expansion of land birds and introduction of alien species.
For these exhausted birds wandering over unfamiliar seas, a ride on a fishing vessel is a great opportunity for survival, especially if they encounter one with a gentle crew that provide shelter, water and food!