One of these prized pieces, a triple-bird group, will be offered for sale at Hansons in Etwall, Derbyshire, on October 24, valued at £50,000-60,000.
The group, which features two smaller characters flanking a larger central figure, is one of four pieces of Martinware consigned from a New York-based vendor with a collective estimate of £100,000.
In addition to the anthropomorphic bird figures, the Martin Brothers also created characterful grotesque models of other creatures, demand for which has increased in recent years. The collection features a frog, a rare survivor from an experimental phase of firing earthenware around 1896-98, which has an estimate of £20,000-30,000, an inkwell valued at £15,000- 25,000 and a Preacher character vessel estimated at £10,000-15,000.
Auction house Dreweatts will also provide a buying opportunity for Martinware enthusiasts in its sale in Newbury on the same day, with a set of four 5in (12cm) high stoneware grotesque figures of imp musicians. Standing on fixed ebonised wood bases, the group dates from c.1890 and is estimated at £12,000-18,000.