Honey Buzzards Take Years to Find Home Again – and Even Longer to Breed
New GPS tracking study reveals that young European Honey Buzzards may wander for half a decade before returning to breed near their natal forests.
The long road to adulthood
For the European Honey Buzzard (Pernis apivorus), growing up is a marathon, not a sprint. A new study published in Animal Behaviour by Pawel Mirski and colleagues from the Universities of Bialystok, Groningen, and Helsinki has revealed that young honey buzzards spend as many as six years wandering between Europe and Africa before finally returning to breed - often within just a few kilometres of their birthplace. The findings shed light on one of the most prolonged and secretive maturation periods known in migratory birds of prey.
Tracking the wanderers
Between 2011 and 2016, researchers fitted 33 young honey buzzards from southern Finland with solar-powered GPS transmitters. Over the next several years, they traced each bird’s migrations between the Nordic breeding grounds and wintering areas across tropical Africa. The aim was to unravel how young birds navigate the long path from fledging to first breeding - a process scientists call natal dispersal. Of the 29 individuals that survived fledging, three-quarters made it to Africa. Yet only six - just 21% - ever returned to Finland in subsequent years, and only two were eventually confirmed to have built nests.
Years spent in Africa before returning north
All tracked juveniles wintered in sub-Saharan Africa during their first year, but none returned to Europe in their second calendar year. Instead, they lingered for years in their tropical wintering zones, covering vast areas of up to 200,000 square kilometres in countries such as Gabon, Nigeria and Chad. “They are essentially wanderers for several years,” said Mirski. “Their first return north doesn’t happen until they’re three, four or even five years old.” One individual, nicknamed Mohammed, remained in Africa for five years before finally crossing the Mediterranean successfully in his sixth year – the longest recorded delay for this species.
Finding home again
Despite their long absence and huge travels, the birds demonstrated an extraordinary ability to home in on familiar landscapes. Every returning buzzard settled in southern Finland, most within 20 kilometres of its natal site. With each return, their average distance from their birth nest halved - from nearly 300 kilometres during their first return to around 130 kilometres by their third. GPS data also showed that their ranging areas in Finland shrank dramatically as they matured: while first-time returnees explored hundreds of square kilometres, older individuals restricted themselves to much smaller, focused territories near their eventual breeding sites.
A gradual apprenticeship
The data suggest that these birds spend several seasons simply learning the landscape before attempting to breed. Their first visits to Finland often lasted just weeks, with arrivals delayed until late June or July - too late for nesting. On later returns, the buzzards reached Finland earlier and stayed longer, eventually matching adult timing. “The first return appears to be a scouting trip,” said co-author Wouter Vansteelant. “They arrive late, explore widely, and gather the experience they need to eventually claim a territory.” By their fifth or sixth year, some birds were building nests, signalling their recruitment into the breeding population.
High risk, high reward
The study also revealed the extraordinary hazards of long-distance dispersal. Nearly 80% of the tracked birds died before reaching breeding age, with most deaths occurring during their first migration or winter in Africa. Shooting, exhaustion and sea crossings took a heavy toll - one in four birds perished during the first migration south, and almost half of those attempting their first return failed to make it across the Mediterranean. Yet for those that survived, the investment paid off: experienced individuals improved their migration timing, reduced stopovers, and arrived earlier each year, increasing their breeding prospects.
Lessons in longevity
Honey buzzards are slow to mature but long-lived - some surviving nearly three decades. This strategy, the researchers argue, allows individuals to delay breeding until they have mastered the immense challenge of transcontinental migration. “It’s a trade-off between survival and reproduction,” said Mirski. “Returning too early, before you’re an efficient migrant, can cost your life.” Such delayed maturity, while rare, mirrors patterns seen in seabirds and vultures, other species that combine long lifespans with extensive travel and territorial breeding.
Why it matters
The findings highlight the complexity of bird life cycles that span continents and years. Understanding how long-lived migrants like the honey buzzard disperse, learn and recruit into breeding populations is essential for conservation, particularly as climate change and habitat loss disrupt migration routes. “These birds spend most of their early lives out of sight,” noted co-author Patrik Byholm. “Protecting them requires international cooperation - from Finland’s forests to Africa’s tropical woodlands.”
October 2025
Read the full paper here
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