Hut­ton’s shear­wa­ter colonies hit hard

Kaikoura Star - - YOUR PAPER, YOUR PLACE - PIPPA BROWN

The im­pact of Novem­ber’s 7.8-mag­ni­tude earth­quake on the en­demic Hut­ton’s shear­wa­ter is worse than first thought.

Hut­ton’s Shear­wa­ter Char­i­ta­ble Trust chair Ted Howard said the earth­quake on Novem­ber 14 hit the birds ex­tremely hard. Only 10 per cent of the chicks may have sur­vived.

‘‘If the birds are to sur­vive long term the trust ur­gently re­quired more fund­ing,’’ Howard said.

‘‘From early over­flights and pho­tos we es­ti­mate that more than 20 per cent of the Kowhai colony and 30 per cent of the Shear­wa­ter Stream colony have been swept away by slips.

‘‘As birds were sit­ting on eggs at the time, it’s likely that at least one of each nest­ing pair was taken to their deaths.

‘‘In slowly re­pro­duc­ing species like the Hut­ton’s shear­wa­ter, the loss of adult birds means a ma­jor im­pact on the pop­u­la­tion.’’

The se­abird only breeds in the high moun­tains around Kaik­oura and its num­bers were al­ready in steep de­cline. Hut­ton’s shear­wa­ter colonies have de­clined from 10 sites known in the early 1960s to two nat­u­ral and one man-made colony to­day.

Ear­lier this month De­part­ment of Con­ser­va­tion Kaik­oura ranger Mike Mor­ris­sey and Hut­ton’s trustee Nicky McArthur in­spected 100 ac­tive bur­rows near the Kowhai re­search hut.

Howard said the bur­rows looked un­dam­aged from the air, but of the 100 bur­rows, 36 were com­pletely blocked, and only one live chick was ob­served.

Al­though num­bers vary year to year some­where be­tween 200 to 1000 birds crash land in the Kaik­oura town­ship dur­ing March and April on their maiden flight to sea.

‘‘The fact that 22 crash-landed birds have been handed in in­di­cates that some chicks have sur­vived, but we sus­pect the sur­vival [rate] this year will be well down on nor­mal,’’ said Howard.

‘‘There is so much vari­a­tion but we es­ti­mate only 10 per cent of the chicks will have sur­vived.

‘‘In ad­di­tion to low breed­ing suc­cess and far above av­er­age loss in adult num­bers, the risk of be­ing dec­i­mated by in­tro­duced mam­mals has in­creased fol­low­ing the earth­quakes.’’

Vast amounts of gravel in the val­ley floors now make the area more ac­ces­si­ble to predators, in­clud­ing pigs who feast on the birds, Howard said.

‘‘If these birds are to sur­vive long term now more than ever be­fore, they will need our help.

‘‘Help­ing these seabirds to sur­vive is some­thing that re­quires help from well be­yond Kaik­oura.’’

PHOTO: SUP­PLIED

Only a few crash­landed birds have been handed in dur­ing March Fly Safe month, and the Hut­ton’s Shear­wa­ter Char­i­ta­ble Trust es­ti­mates that up to 10 per cent of chicks have been lost due to last year’s earth­quake.

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