I got a translation of the article from the German Wikipedia. Here's an excerpt:
Perytons are in radio astronomy short radio signals having a length of a few milliseconds, which probably terrestrial are origin. The Perytons are named after mythical creatures .
In radio astronomy, terrestrial are noise is always a problem. A well-known noise signal are millisecond bursts of radio emission after a mythological hybrid creatures are called Perytons. Probably these signals are sidelobes captured the antenna. The Perytons occur at high altitudes above the horizon and show no frequency dispersion in contrast to the closely related radio bursts Fast . Perytons often occur as a result of periodic bursts. As a generation mechanisms are recombination of charge carriers three or synchrotron radiation of a collapsing magnetic field are discussed.
They can apparently come from aircraft, atmospheric phenomenon or solar radiation.
This paper and this paper go into more detail.