A Little HistoryThe canvasback (Aythya valisineria) was among the most expensive wild birds in nineteenth-century America, and its reputation rested on a diet: on the Chesapeake and the Susquehanna flats it fed heavily on the roots of wild celery, Vallisneria, which is written into its scientific name and was generally credited with the nutty, un-fishy flavour that separated it from other divers. Chesapeake market hunters shipped them north to the city markets by rail, and Delmonico's — where Charles Ranhofer was chef from 1862, with a break in the later 1870s, until 1896 — put them on the menu at prices that made them a byword for luxury; The Epicurean (1894) devotes a run of consecutive numbers to them, broiled, roasted, and garnished with hominy in the Maryland manner. Market hunting on that scale is why the recipe now reads as a historical document: the trade in wild waterfowl was closed down by a sequence of federal measures culminating in the Migratory Bird Treaty Act of 1918, and canvasback numbers have been managed cautiously ever since. The technique, though, is the ordinary treatment for a small lean bird — flattened, oiled, seared over coals, and laid on a buttered brown sauce sharpened with lemon.