The arts supplement of the daily Frankfurter Allgemeine Zeitung is to German high culture what the Times Literary Supplement is to English letters: sober, authoritative, demanding and not a little po-faced.

So the reaction can be imagined to the news that for years the leading conservative newspaper has been purveying the Weltanschauung of Donald Duck. A recent edition was found to contain no fewer than 10 headlines and captions taken from the bubble captions of Donald Duck comic strips.

Confronted with overwhelming evidence by reporters from the weekly news magazine, Der Spiegel, two FAZ journalists owned up last week. Patrick Bahners, 33, and Andreas Platthaus, 34, admitted to having slipped "Donaldisms" into captions and headlines about everything from classical Greek theatre to Chopin.

One recent heading, taken from a cartoon strip, ran above a critique of a book on advertising: "Sparkling water, duck's wine, costs little and tastes fine". They even slipped some extracts into the texts of their own articles.

The two journalists are members of a society called Donald that promotes the cartoon character.

"We regard ourselves as scientists," Mr Platthaus said yesterday. "We study life in Duckburg in much the same way that normal scientists deal with our world."

Members of Donald have an annual "Day of Struggle" on April 1 and, in keeping with the conventions of the comic strip world, they do not applaud but shout: "Clap. Clap. Clap."

Mr Platthaus said his colleague had been slipping Donaldisms into the newspaper for 10 years. "When I joined the paper, three and a half years ago, we combined our efforts and the number of Donaldisms increased. It has been really intense in the last two years".

So intense, in fact, that a reader of the rival Süddeutsche Zeitung remarked in a letter on the similarity between the cartoon duck's utterances and some material in Germany's most respected daily. Mr Platthaus said he thought that it was that letter that had aroused the interest of Der Spiegel's investigators.

Asked about the reaction at FAZ, he said: "Up to now, there has been no reaction." But he added: "Because the editor is on holiday."