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- Written by Clyde McMillan-Gamber Clyde McMillan-Gamber
Two kinds of related oceangoing birds, Wilson’s petrels and Leach’s petrels, have several characteristics in common.
These 8-inch-long birds are fascinating to watch dancing on the water while eating plankton, small crustaceans, and tiny fish from the open oceans’ surfaces. I have viewed their entertaining feeding habits through videos on computer screens.
While feeding, their wings are stretched out to catch the oncoming wind, which holds them just over the ever-pulsing swells.
Meanwhile, their long legs alternately dangle and hop rhythmically in harmony with their wings, which pushes the petrels forward on top of the shifting waves as the birds pick morsels from the water’s surface with their beaks. Their wind-filled wings keep them from sinking as they bound along.
Both kinds of petrels often patrol alone to get food. But sometimes they flutter gracefully over the oceans in loose little groups, each bird soaring into the wind on outstretched wings and pattering and bouncing lightly on the water on foot.
They appear to dance on the water, but it’s their wings that hold them above the constantly heaving swells.
Near lookalikes, both kinds of petrels are dark brown, with white on th base of their tails. Both have nostrils in a fused tube on top of their beaks. And genders are similar in both species.
Both petrel species annually raise one chick per mated pair in a crevice between rocks or in soil burrows in nesting colonies on islands in the oceans. Both parents of each pair feed their one youngster until it can fly and be independent.
Wilson’s petrels nest on islands around Antarctica during its summer, our winter. Post-breeding Wilson’s drift north over the oceans during our summer to feed until our autumn, when it’s time to return to Antarctica to nest again.
Leach’s petrel pairs rear offspring in summer on islands in the North Atlantic. Nesting in different hemispheres at different times reduces direct competition between these related petrels for food on ocean swells, which is one reason why both species are so abundant.
Every niche on Earth is inhabited by at least one form of life. The unique and intriguing petrels are entertaining to watch gracefully dancing and feeding just above ocean swells.
And they can be observed by videos on computers, if not in person.
Clyde McMillan-Gamber is a retired Lancaster County Parks naturalist.