PENGUINS RETURN 2400 MILES TO ROOKERY

Press, Volume XCIX, Issue 29401, 31 December 1960, Page 15

PENGUINS RETURN 2400 MILES TO ROOKERY

Two Adelie penguins, banded at Wilkes station, in the Antarctic, and flown to McMurdo Sound in December 1959, have found their way home to their rookery at Wilkes, 2400 miles away, says a report from the National Science Foundation, one of the organisations sponsoring American research in the Antarctic.'

This is the first experimentally controlled evidence of a penguin migration over so long a distance. It indicates a strong desire on the part of the penguins to return to their specific nesting site, says the report. Reports of the unique return came to the American base on Ross Island several weeks ago. but communications difficulties delayed the release of furthei details.

The two penguins were among five Adelies banded at Wilkes by Mr R. L. Penney, of the zoology department of the University of Wisconsin. Mr Penney is at Wilkes studying the orientation and sexual behaviour of the Adelie penguine. He has spent two consecutive years at Wilkes and is scheduled to return to the United States at the end of this summer.

In December, 1959, a VX-6 squadron aircraft flew five of Mr Penney’s banded penguins from Wilkes to McMurdo. where they were checked and set free by Mr J. Dearborn, a Stanford University biologist investigating the marine ecology of McMurdo Sound.

No trace of any of the five birds was seen again until the middle of November this year, when Mr Penney reported the return of two of the banded penguins. Not only did the two return to the Wilkes rookery, but they returned to the same colony that they had inhabited last year. Mr Penney doubts, however, that the two birds returned as a pair. As reasons, he points out that the two birds returned on two successive days and that they are both apparently males. He believes a third bird may also have returned, but he can not confirm this. A male Adelie, without a band but showing feather wear at the base of its flipper returned to the same nest from which one of the five was taken last year. The report says that this is a fair

indication that the bird had lost a band as do one or two per cent, of all banded birds. Faithfulness to the nest on the part of hundreds of other observed penguins in the rookery, Mr Penney says, tends to support this assumption. The remaining two penguins which were flown to McMurdo and released are now unlikely to return.

The significance of the penguin return, Mr Penney says, is the distance of from 2200 to 2400 miles covered in skirting the continental coast via the pack ice. The precise environmental cues utilised by the Adelie in such long travels is still unknown. Also unknown is how far the Adelies actually travel during the winter.

Mr Penney has found that the extreme nest-site stability and the desire to return to the former nesting site is very important to his study of territory and pair formation. The homing ability of the Adelie is dependent on response to water by the watersky phenomenon and to land by coastal landmarks. Watersky is the dull, neutral-coloured appearance of the sky near the horizon, which is caused by reflection of the colour of the sea and which indicates open water when seen over an ice-covered sea. Mr Penney believes that the position of the sun and an innate sense of time may be of help to the penguin in homing. He has experimented to a limited extent with displacing penguins by transporting them to relatively remote areas of the icecap around Wilkes station, but has not yet had any decisive results. In his regular penguine banding experiments. Mr Penney estimates that at November 15, from 75 per cent, to 85 per cent, of all banded adult penguins returned to the rookery, says the report.