Searches for color-banded Great Cormorants (Phalacrocorax carbo) were carried out during 2002-2004 at an inland roost in Spain in order to determine the origin of the birds, to measure the length of stay and within- and between-seasons site fidelity in relation to age. Contrary to expectations, neither the stay duration at the roost nor the site fidelity depended on age. The low stay duration (the majority of the birds were sighted only once) and return rates suggest nomadic behavior of the wintering cormorants. The cormorants that stayed longer at the roost also returned there more times during one season, suggesting that site fidelity may have an adaptive value for wintering cormorants.