As the population of the cranes increases, unforeseen problems have emerged.
- Increased risk: Although the population has increased from about 10 to more than 1800,
approximately 70% of the cranes gather at the five major feeding stations
in winter. Therefore, there is the increased risk of losing a high proportion
of individuals in the population due to accidental contamination or infectious
- Limited genetic diversity: Because the population in Hokkaido was founded by a small number of individuals,
genetic diversity in the population is limited. The loss of genetic diversity
could cause a number of problems. For example, immunity to disease and
reproductive capacity may have been lowered due to loss of genetic diversity.
- Habituation: Over the years, the cranes have become habituated to people, livestock
and infrastructure. Below are examples of specific problems associated
In this example, the tiny white dot in the wetland is an adult crane sitting
on a nest. The wetland is surrounded by pastures.
The cranes have gradually adopted environments modified by people as their habitat.
Many cranes visit cattle farms throughout the year. Occasionally, the
cattle frightened by cranes run into objects and injure themselves.
Also, the cranes sometimes cause damages to property when a crane mistakes
the reflection of itself on a vehicle or window pane as an invader to its
Some cattle farmers are concerned that the cranes may bring infectious diseases to their farms.
Some cranes have been rescued from or found dead in cow manure slurries.
Interfering with farming
Also, some habituated cranes cause damage to crops.
Therefore, some local farmers feel resentment towards the cranes.
Traffic accidents involving automobiles and trains continue to occur. Also,
some cranes still fly into power lines.
We help government agencies and local residents by proposing conservation
strategies and practical solutions to problems in order to facilitate protection
of the cranes and their habitat.
Exposure to chemicals
Because the cranes are spending an increasing length of time in cultivated
fields, stock yards and drainages near human habitation, an increasing
number of cranes has been exposed to chemicals. Mortality may possibly
occur due to ingesting a type of insecticide used widely in cornfields
and due to lead poisoning.