Ixodes uriae White is the only tick species found in Antarctica, and in our research area at Palmer Station it feeds predominantly on Adélie penguins. At the beginning of the summer the ticks leave their off-host aggregation sites, feed on penguins, then subsequently return to their off-host habitats, where they remain until the next summer (Benoit et al. 2007). These ticks have been implicated as a competent vector for Borrelia spirochetes (Olsen et al. 1993) and tick-borne viruses (Nuttall 1984), and are thought to impact development, cause anaemia, alter the thermoregulation, and even lead to the death of penguins (Gauthier-Clerc et al. 1998, Mangin et al. 2003). In this report, we note a striking increase in the number of fed ticks found near Adélie penguin rookeries in 2007 compared to 2006, suggesting that the longer and warmer summer of 2007 may have permitted more ticks to find their hosts. High levels of parasitism could be detrimental to the already declining Adélie penguin populations near Palmer Station (Fraser & Patterson 1997).