Flexibility of Continental Navigation and Migration in European Mallards

Abstract

The ontogeny of continent-wide navigation mechanisms of the individual organism, despite being crucial for the understanding of animal movement and migration, is still poorly understood. Several previous studies, mainly conducted on passerines, indicate that inexperienced, juvenile birds may not generally correct for displacement during fall migration. Waterbirds such as the mallard (Anas platyrhynchos, Linnaeus 1758) are more flexible in their migration behavior than most migratory songbirds, but previous experiments with waterbirds have not yet allowed clear conclusions about their navigation abilities. Here we tested whether immature mallard ducks correct for latitudinal displacement during fall migration within Europe. During two consecutive fall migration periods, we caught immature females on a stopover site in southeast Sweden, and translocated a group of them ca. 1,000 km to southern Germany. We followed the movements of the ducks via satellite GPS-tracking and observed their migration decisions during the fall and consecutive spring migration. The control animals released in Ottenby behaved as expected from banding recoveries: they continued migration during the winter and in spring returned to the population’s breeding grounds in the Baltics and Northwest Russia. Contrary to the control animals, the translocated mallards did not continue migration and stayed at Lake Constance. In spring, three types of movement tactics could be observed: 61.5% of the ducks (16 of 26) stayed around Lake Constance, 27% (7 of 26) migrated in a northerly direction towards Sweden and 11.5% of the individuals (3 of 26) headed east for ca. 1,000 km and then north. We suggest that young female mallards flexibly adjust their migration tactics and develop a navigational map that allows them to return to their natal breeding area.

As the Duck Flies—Estimating the Dispersal of Low-Pathogenic Avian Influenza Viruses by Migrating Mallards

“…Furthermore, the empirical distributions derived from the migratory durations and distances were derived from a relatively small sample, and might not be representative of overall mallard migration patterns. However, we are confident that our tracking data sample is quite representative of autumn migrations from Ottenby, as the patterns derived from both the observed and simulated migrations corroborate previous tracking studies (van Toor et al, 2013) and ring recovery data (Gunnarsson et al, 2012). The ring recovery data might have also introduced a bias into our results.…”

Variability among autumn migration patterns of Mongolian Common Shelducks (Tadorna tadorna)

“…This is the first satellite-tracking study of the Common Shelduck describing the autumn migration of this widespread species, providing the first descriptions of the individual diversity in movements, timing and habitat use on autumn migration from the post-breeding grounds prior to converging on the wintering quarters along Chinese coasts. The results conformed with studies of freshwater dabbling ducks in continental western Europe that also showed flexibility in navigation and movement patterns during autumn migration (van Toor et al 2013;Gehrold et al 2014). Notably, the early arrival in Bohai Bay or Shandong Peninsula by two females (2173,2220) allowed them to migrate southward to Zhejiang and Jiangsu coasts for winter.…”

Great flexibility in autumn movement patterns of European gadwalls Anas strepera

“…In 2009 and 2010, 23 individuals were equipped with backpack satellite transmitters by use of the harness described by Roshier and Asmus (2009). However, because of equipment failure, which is common in ducks (Van Toor et al 2013), only six males and one female could be tracked after leaving the moulting site. Note that the initial sample was already male‐biased (18 males, 5 females), as we tried to avoid using the heaviest device (type 1, see Table 1) for lightweight females.…”

“…This strategy implies that individuals acquire the essential knowledge about the location of suitable sites and about the pathways that connect them by following experienced conspecifics or by performing independent exploratory movements (Wolff 1970). Furthermore, this strategy requires a relatively high degree of flexibility, thus enabling individuals to adjust the direction and distance of migration according to the distribution of habitat patches that offer suitable conditions during a particular life history stage (Van Toor et al 2013).…”