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Monday, 11 July 2016

Storm Petrel ringing on the Magharees

For Storm Petrel ringing on a mainland site you need a loud amplifier, a recording of Storm Petrel 'song' on constant loop, a mist net, and a qualified ringer, in this case, Declan Manley from Co. Offaly. In the course of full darkness on the night of 6th/7th July - barely 4 hours at this time of year - he caught and ringed 90 Storm Petrels from a small headland overlooking the Magharee Islands. The islands host about 1100 nests on several of the islands, with the main numbers nesting in burrows under turf clumps on Illaunammil and in stone walls on Illauntannig.

Storm Petrel, Magharees, 7th July 2016 (Michael O'Clery).

Storm Petrels only return to their nesting colonies on offshore islands in full darkness and will otherwise avoid land, even on nights with a bright moon. The reasons are simple. On land they are slow and vulnerable, and prone to being eaten by gulls. The gulls however, are not equipped to see in full darkness, so that is when the petrels make a run for it to feed chicks, or swap over for incubating duties on the nest.

Storm Petrel, Magharees, 7th July 2016 (Michael O'Clery).

Although the tape of Storm Petrel song was probably not audible (to humans) on the breeding colonies on the Magharee islands over a kilometre away, Storm Petrels will often fly close inshore on these dark, moonless night, as evidenced by several being caught in the mist net within a few seconds of the song being played. 

Storm Petrel, Magharees, 7th July 2016 (Michael O'Clery).

Younger birds wander throughout the Storm Petrel's range in the Atlantic seeking out their own colony. Most of these long-lived birds will not breed until their fourth or fifth year and spend much of their early years 'visiting' other colonies in summer, and it is mostly these younger, wandering birds, Declan believes, which were mist-netted and ringed.