The Coat of Arms is made up of a collage of different techniques by several people, just like the composition itself is an amalgam of other coats of arms.
I've lifted this description straight from the old Leodis site
In 1626 a Royal Charter of Charles I incorporated the Borough of Leeds when the wealthy Sir John Savile, MP for Yorkshire, was elected the first council member of the Borough. The coat-of-arms displayed a fleece, supported by silver owls on a blue field. The fleece represented the staple trade of the town whilst the supporters came from the arms of Sir John. Sir John had recently become a landowner in Leeds and he gave some land in Headingley for building a church, which became the first St.Michael's in Headingley.
|Following the restoration of the monarchy in 1662 the chief inhabitants of the town petitioned Charles II for a new charter. The charter was granted on the 2nd November that year. With this charter the chief citizen became the mayor of the town. The first mayor of the town was Thomas Danby whose arms included three mullets argent, or three silver five-pointed stars to you and me. The stars were added to the arms.|
The arms were not settled until 1836 when the Leeds Corporation was reconstituted under the Municipal Corporations Act 1835 and the Borough Seal now comprised the full complement of blue shield, owl supporters, the crest and the motto, 'pro rege et lege'
An important citizen of Leeds in 1920 was Alderman Sir Charles Wilson MP, a Freeman of Leeds and London. He was concerned about the legality of the coat-of-arms as it was not registered at the College of Heralds. It was decided to submit the matter to the College.
The arms received the sanction of the College on the 7th November 1921. Above the shield is the closed helmet used by Civic Authorities with a crest-wreath and covering in the principal colours of the arms, gold and blue.
The full coat is now described in heraldic terminology as: Shield: azure, a fleece or, on a chief sable three mullets argent; Crest: on a wreath or and azure, an owl proper; Supporters: an owl proper ducally crowned; Motto: 'Pro rege et Lege'.
The three owls were embroidered by Audrey Gabbitas in a variety of techniques. The wings are canvaswork, the bodies hand embroidered and padded, the feet made of wire and wrapped with perle thread and the crowns are gold leather. The lamb and stars by Colleen Nicoll and the helmet and plume by Anne Darch were all appliqued. Kate Russell and Sue Hodgson hand embroidered the ribbon.
There's a very interesting article here about the owls of Leeds, apparently they are European Eagle Owls