The nightingale, a small songbird weighing about 25 grams, undertakes an annual migration of approximately 9,000 kilometers, according to multiple reports. The bird arrives in Sweden around the turn of April–May and begins its southward journey in August–September, traveling via Egypt and eastern Africa to overwinter in tropical southeastern Africa.
Researchers at Lund University used advanced ultra-light sensors to track the birds' behavior in detail. The analyses covered eleven complete migrations from ten nightingales caught outside Lund, spanning both autumn and spring migrations over three years. The results show a clear pattern: nightingales perform four to five consecutive night flights, interspersed with daytime breaks when they barely move. This strategy minimizes energy consumption during the hottest hours and avoids intense desert heat. During the quiet breaks in desert areas, the birds do not replenish energy but live on reserves built up before migration.
It is an extreme behavior. They push through several nights in a row and basically shut down completely during the days.
Pablo Macías-Torres, a biology researcher at Lund University, described the behavior as extreme: "They push through several nights in a row and basically shut down completely during the days." Professor Anders Hedenström added, "These birds do not take chances. The whole strategy is based on them having loaded enough energy before they begin the most inhospitable parts of the journey." Macías-Torres noted that understanding how changing environments affect the nightingales' ability to complete the journey will be crucial in a rapidly changing world.
These birds do not take chances. The whole strategy is based on them having loaded enough energy before they begin the most inhospitable parts of the journey.
The next step is to understand how changing environments affect the nightingales' ability to complete the journey. That will be crucial in a world where both climate and habitats are changing rapidly.