Migration is an adaptive response to the seasonal ... monarch butterflies migrating south through North America in the autumn have no sexual organs — these only develop the following spring ...

For example, eggs could be laid so late that they are unable to develop into adults, or adults could emerge from their chrysalises when conditions are no longer suitable for fall migration.

Many types of geese and swan arrive to the UK in autumn to find food and escape the cold winter conditions in the Arctic. (Arterra Picture Library / Alamy Stock Photo) Migration can happen around ...

For the first time in recent history, the stock of international migrants is likely to decline as new migration has slowed and return migration has increased. The global average cost of sending $200 ...

RAUSU, Hokkaido—Salmon are at the peak of their upstream migration in the rivers of the ... swimming upstream is a symbol of the arrival of autumn in Shiretoko,” said Katsunori Seki, an ...

Every autumn, spider crabs migrate from the Welsh ... The basking shark is the second largest fish in the world. Their migration routes remain a bit of a mystery. They can be spotted off the ...