Mayor Makes It Official: It Was a Big Year for Isabella and Jayden Edward Reed/N.Y.C. Mayor's Office, via flickr An Isabella (center), a Jayden (right) and an unidentified -- but definitely named -- toddler (left) appeared with the mayor at City Hall on Wednesday. Looking pink-skinned, diminutive and a little bit wrinkly, Mayor Michael R. Bloomberg appeared in City Hall's Blue Room on Wednesday morning to deliver one of the year's more adorable bundles of news: the way we name our babies now. Cooing, remarkably well-behaved bearers of the leading monikers had been brought to the news conference, parents in tow, to commemorate the occasion. The mayor, in a more upbeat mood than his often-cranky one, seemed delighted with his young guests. Out came the onesies and complimentary bibs, which featured a seal of the city and the insignia "Official N.Y.C. Baby." The mayor pinned a bib on Jayden Marthone, who appeared unimpressed. The city gained 623 Isabellas and 851 Jaydens last year, out of 123,029 New York-born babies in all. Procreative activities waned a bit from 2010, with the number of city births slipping 1.4 percent. Brooklyn topped the births-by-borough list with 41,303 babies, although few of those will reflect the ultimate in hometown pride: Brooklyn, once a somewhat popular name, ranked 141st on this year's list, behind Santiago and London. Michael -- "a fine name," as Mr. Bloomberg put it -- moved up two spots to No. 5, a decent showing for a name that had ruled for