Cranes from Ostrava have postponed their southward migration

Common cranes (also known as Eurasian cranes) are birds which migrate annually from Central Europe to warmer habitats in southern Europe, where they spent the winter. The young cranes do not automatically know the route; they have to learn it from their parents. It was a great surprise to nature conservation experts from Ostrava’s zoo when they discovered that this year’s chick – which has been fitted with a special transmitter to enable its movements to be tracked – has decided not to leave its winter home yet. It is not clear whether this family of cranes will remain here all winter, or whether they will eventually decide to fly south. It also remains to be seen whether the young cranes learn the route successfully.

Ostrava was the first zoo in the Czech Republic to use a GPS-GSM transmitter to monitor the movements of cranes – and now it is enabling experts to track this young crane’s precise location. Cranes learn the migration route from their parents, and they usually set off on their southward journey during the first few weeks of the winter. Markéta Ticháčková, a field worker at the zoo and the coordinator of the crane colour-coding system in the Czech Republic, recalled:

Our young crane flew to a gathering point in Germany in October, where – accompanied by its parents – it joined the large flocks preparing for the migration. We waited impatiently to see which route they would take. But to our great surprise, instead of flying to warmer regions, the entire family returned to its nesting site here.

First, the young crane and its parents (plus another adult crane) found food in a beet field after the harvest, and then a group of 31 cranes began to seek out food in the stubble of a cornfield. But “their” crane is not the only one in this flock to be colour-ringed (a system used throughout Europe to track crane migrations – see www.icora.de). Nor is it the only young crane to have returned to its birthplace instead of undertaking the long journey south. Ticháčková gave more details:

There is another family in the flock whose chick we colour-ringed in the summer – we use unique individual ring combinations. That family returned too. Now they are hunting for food with the rest of the flock during the day, but at night they go elsewhere – to a pond where their original nesting site was.

The arrival of the family at its nighttime home is captured on this video.

Cranes do not mind cold weather, but it’s essential that they can find enough food – and snow-covered ground reduces their ability to do so. So far this winter, more snow has fallen in the cranes’ normal winter homes in southern Europe than has been the case here. However, František Příbrský, head of the In Situ project at the zoo, adds:

Despite the current snow in southern Europe, winters here in Central Europe still tend to be much colder – so we’re waiting to find out where the cranes will be in January, when snowfall is at its highest. We won’t have to wait long to find out…

Source: ZOO Ostrava; Photograph: Markéta Ticháčková