Blackcap Warbler Migration Facts

Location/Distance

• The blackcap warbler migrates from Central Europe and Russia to the United Kingdom, Iberian Peninsula, the Mediterranean and Sub-saharan Africa.

• Their journey varies in distance and can take between 32 and 88 days.
  
  

Mating

• These birds often mate with other birds who return to the breeding ground at the same time as themselves.

• For example, the birds returning from England mate with other birds returning from England.

• This can lead to assortative mating.

• The males are territorial.

• In migratory populations (the warblers that migrate), sexual seleciton is driven by female selection.

• In sedentary populations (the warblers that don't migrate), sexual selection is driven by male-male competition
  
  

Feeding

• They feed mostly on berries but also eat insects and meal worms.

• They are very flexible feeders

• They can acquire 75-90% of their daily energy in 10% of the time available for eating.

• During a stopover in migration they quickly gain a lot of weight.

• Larger birds have enough fat reserves to skip the stopover.

• They are able to reduce size of their digestive tract during migration.
  
  

Migration Cues

• Endogenous rhythm that is synchronized with photoperiod (light/dark cycle).

• Migratory inheritance: migratory activity and direction of migration is inherited from their parents.

• Nocturnal migratory restlessness is another migration cue.
  
  

Navigational Mechanisms

• They use the magnetic field at certain intensities.

• They use constellations in night sky as landmarks. They know the constellations rotate around the North Star and use this to find their way.