‘Planet Earth: Extreme Journeys’
Do all animals or species have an innate sense of migration or do certain animals need a pack leader to kick off the journey? Which animals fall into the latter category?
Zack: Well, like all nature vs. nurture questions, the answer is both. Animals have both an innate and a learning capacity for migration. Really, the most interesting in the latter category is something we see every year, and those are the geese migrations that happen around us. Geese migrate during the day, unlike songbirds, which are night fliers. Geese, of course, fly in groups that are most often family groups of a sort: the older females and her collective female young from previous seasons who get male partners from outside that group and they fly as family units. Because they fly by day, apparent landmarks are really important in their migrations. In that sense, the knowledge of the older individuals leading the migration is really key to their success. Geese use mountain ranges and other visible landmarks in their impressive journeys from our areas in the winter that have no ice all the way up to the Arctic. In the case of Oregon, we have Canada Geese, Cackling Geese, and Tundra Swans all in that category of making these long movements, but making them by day and apparently where knowledge of the landscape is just really important.
Can you give another example of the kind of landmarks geese use during migration?
Zack: In addition to specific mountain peaks, geese look for bays and estuaries that over time individuals have learned that are part of their migratory journeys. The estuaries and the wetter areas would be those areas where they may drop down to feed at the end of the day and take off from the next day. It’s just interesting to me that in the case of geese and swans, they know the road marks and they follow those and daughters learn them from their mothers to guide subsequent migrations.
In your own personal field experience, have you witnessed an actual migration, journey, or flight occur and what impact did this have on your professional and personal outlook about nature and the basics of survival?
Zack: As a scientist for the Wildlife Conservation Society and having the great opportunity to study in different places I get to look at and observe migration almost every year. Particularly, my recent work has been in Arctic Alaska where migrants come to breed in the summer months literally from every continent and every ocean on earth. So, if you can’t appreciate migration in the Arctic, then you just simply can’t appreciate migration.
I had the opportunity to go to South Korea to look at Arctic-bound shore birds there because several shorebird species in Arctic Alaska migrate through Asia as part of this international aggregation. In recent years, we’ve had these worldwide concerns over avian flu and whether wild birds were in fact carrying the infection of avian flu, which has been rampant in poultry in Southeast Asia. The easy transmission between wild birds and poultry birds has been historically true so there is great concern regarding these recent outbreaks of avian flu, whether it was getting into migratory birds and whether in turn migratory birds would pass it to others and this might, in theory, be a mechanism for getting avian flu into the U.S.