The Canada goose was found by Jason Summers in January 1999. It consists of a glider pulling a tagalong.
At the time of its discovery, the Canada goose was the smallest known diagonal spaceship other than the glider, but this record has since been beaten, first by Orion 2, and more recently by the crab.
It was discovered in January 1999 by Stephen Silver that Canada geese can be welded together by their wings, creating an extensible spaceship. Gabriel Nivasch, later that same month, reported that because the swan uses the same wing, swans and Canada geese can be welded together. He also found that a pair of big gliders pulling a tagalong can replace the glider at the front end of the Canada goose.
Two Canada geese welded together, as discovered by Stephen SilverRLE: here
A swan and a Canada goose welded together, as discovered by Gabriel NivaschRLE: here
A Canada goose with the front glider replaced by a pair of big glidersRLE: here