The puf­fin has adopted a clever hunt­ing strat­egy

Wicklow People (West Edition) - - LIFESTYLE - JIM HUR­LEY’S

THE At­lantic Puf­fin with its huge, colour­ful, par­rot-like bill, its very large, pale, sum­mer cheek patches and what of­ten ap­pears to be a com­i­cal ex­pres­sion on its face, is a favourite of photograph­ers and is an ea­gerly sought-af­ter sub­ject in seabird and wildlife pho­tog­ra­phy.

Seabirds like the North­ern Gan­net, our largest seabird, hunt for sur­face-shoal­ing fish by fly­ing over­head un­til they spot their prey below, then par­tially fold­ing their wings to form an an­chor-like body shape they plunge-dive from a height hit­ting the wa­ter head­first at a speed that drives them un­der­neath to grab a hard-earned meal.

Puffins adopt a dif­fer­ent strat­egy; they float high in the wa­ter on the sur­face, and when they spot a shoal of fish like sandeels below they up­end and dive us­ing their stubby wings to ‘fly’ un­der­wa­ter in pur­suit of their prey.

In the cur­rent is­sue of the sci­en­tific jour­nal ‘Bi­ol­ogy Let­ters’, a MaREI re­search team to­gether with the Zoo­log­i­cal So­ci­ety of London, an in­ter­na­tional con­ser­va­tion char­ity, car­ried out a two-year study of for­ag­ing puffins off the Sal­tee Is­lands in the sunny south-east.

MaREI is the Cork-based ma­rine and re­new­able en­ergy re­search, de­vel­op­ment and in­no­va­tion cen­tre sup­ported by Sci­ence Foun­da­tion Ire­land. The team com­prises in­ter­na­tion­ally recog­nised ex­perts from Irish uni­ver­si­ties, re­search groups and in­dus­try part­ners.

The au­thors of the re­port found that in­stead of the birds swim­ming aim­lessly about in search of food, the puffins drift on the tidal stream and let the cur­rent trans­port them to suitable feed­ings patches.

A tidal stream is a cur­rent as­so­ci­ated with tides. Tides cause the wa­ter in the sea to rise and fall so the move­ment is ver­ti­cal; the tidal stream is the as­so­ci­ated hor­i­zon­tal cur­rent. Tidal streams usu­ally flow close to the coast­line and since they can be quite strong it makes sense that life forms would evolve to take ad­van­tage of the free ride.

The au­thors found that by drift-hunt­ing in this way, the birds save en­ergy that would oth­er­wise be used in look­ing for prey. En­er­getic mod­els sug­gest the cost of for­ag­ing trips us­ing the drift strat­egy is 28–46% less than fly­ing be­tween patches. It ap­pears likely that the birds have evolved to ex­ploit the tidal steam and that the strat­egy is learned be­hav­iour.

The au­thors sug­gest that the drift strat­egy they ob­served in puffins may be far more wide­spread among other species of seabirds than cur­rently thought.

At­lantic Puffins drift­ing on the tidal stream.

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