Get­ting a Head Start

Canadian Wildlife - - WILD THINGS -

Pro­tect­ing tur­tle eggs from preda­tors to in­crease the num­ber of suc­cess­ful off­spring plays a key role in tur­tle con­ser­va­tion. Yet even then, the prob­a­bil­ity of tiny hatch­lings sur­viv­ing to adult­hood is in­cred­i­bly low. To boost those odds—es­pe­cially for species and lo­cal pop­u­la­tions in ex­treme peril—some pro­grams use a prac­tice called “head­start­ing.” It in­volves rear­ing hatch­lings in cap­tiv­ity for any­where from a few months to al­most two years be­fore re­lease.

“We’re just try­ing to get them up to a size where they can more eas­ily avoid pre­da­tion,” says An­drew Len­tini, cu­ra­tor of am­phib­ians and rep­tiles at the Toronto Zoo, which has been run­ning a Bland­ing’s tur­tle head­start­ing pro­gram in the re­cently cre­ated Rouge Na­tional Ur­ban Park since 2012.

The na­tive adult Bland­ing’s pop­u­la­tion in the Rouge River wa­ter­shed is so de­pleted due to road­kill, nest pre­da­tion and a lack of habi­tat con­nec­tiv­ity, that the zoo sources the eggs used in its pro­gram from the On­tario Min­istry of Nat­u­ral Re­sources and Forestry. The MNRF gets them from “non-vi­able” nests else­where in the prov­ince, usu­ally un­cov­ered dur­ing high­way con­struc­tion. The zoo hatches and raises the young for about two years and then, each year in June, re­leases 50 Bland­ing’s tur­tles into the park. All of them are marked, tagged and some are equipped with ra­dio trans­mit­ters for sub­se­quent mon­i­tor­ing and track­ing.

One ben­e­fit of the in­door rear­ing: these tur­tles are al­ready as big as a typ­i­cal six- or seven-year-old nat­u­rally reared Bland­ing’s. Even so, not all will reach adult­hood. How­ever, Len­tini says pop­u­la­tion mod­els in­di­cate that re­leas­ing 50 tur­tles a year for 17 to 20 years will create a sta­ble, self-sus­tain­ing adult pop­u­la­tion of 150 Bland­ing’s in the area. “We’re into our fourth year of re­leases, so we’ve got about an­other 15 years to go.”

Across the coun­try, in B.C.’S lower Fraser Val­ley, An­drea Gie­lens, project lead for B.C. wet­lands wildlife at Wildlife Preser­va­tion Canada, runs a sim­i­lar pro­gram in tan­dem with the Greater Van­cou­ver Zoo for the en­dan­gered coastal pop­u­la­tion of the western painted tur­tle.

“Our goal for re­lease is a min­i­mum size of 30 grams,” says Gie­lens. “We want to make sure that we’re not just throw­ing a bunch of tiny tur­tles out there that are go­ing to get pre­dated right away. We want to make sure that they are go­ing to sur­vive to breed.”

Un­der the pro­gram, which be­gan in 2013, they rear 175 to 200 tur­tles a year. The eggs are col­lected from at-risk nests in late May to early July by Gie­lens and oth­ers on the project, and typ­i­cally re­leased in Au­gust or Septem­ber the next year. Since male western painted tur­tles reach ma­tu­rity around seven or eight, and fe­males a lit­tle later, the cur­rent mile­stones are lim­ited to track­ing the tur­tles’ sur­vival and growth. But soon they’ll be­gin look­ing for signs of breed­ing and then suc­cess­ful nest­ing, says Gie­lens.

“Then we’re go­ing to start look­ing at the sur­vival of those off­spring and their growth over time. Even­tu­ally we’ll have our first breed­ing of ba­bies born from our aug­mented pro­gram. But that’s quite a few years off.”

Newspapers in English

Newspapers from Canada

© PressReader. All rights reserved.