Meet Natator: the Cinereous Vulture who swam for his life between Portugal and Spain

Natator was rescued on an international mission, recovered and released back in nature as part of the LIFE Aegypius Return project.

The Cinereous Vulture (Aegypius monachus) breeding colony in the Tejo Internacional Nature Park is the largest and oldest in Portugal. The species settled here in 2010, around four decades after it became extinct as a breeder in the country. In 2024, this colony recorded at least 61 nesting pairs, 15 or 16 of which on the Spanish margin of the river. The colony benefits from cross-border collaboration, which sometimes proves essential for the birds' survival, as can be seen in Natator's story.

The importance of close monitoring

On April 21^st, 2024, a little Cinereous Vulture hatched at Herdade da Cubeira, in the Tejo Internacional Nature Park. On July 18^th, at 89 days of age, it was ringed with the code 5S and fitted a GPS transmitter, which allows the project teams to monitor all his movements and behaviour. In less than a month, it took its first flights, always in the Tejo Internacional region, often landing on the riverbanks. In the valley, near the water, network coverage is unreliable, so GPS data is sometimes received intermittently.

Despite the challenges in receiving GPS data, Paulo Monteiro, a technician from SPEA (Portuguese Society for the Study of Birds) responsible for monitoring the colony, noticed that 5S had been stationary by the river for an unusually long time. The accelerometer data showed that the bird was alive, but might be in trouble. Since the bird was on the Portuguese bank of the river, an area difficult to access and observe from that side, Paulo contacted the rangers (Agentes del Medio Natural) from Junta de Extremadura (JEx), who promptly provided a team to observe the chick from Spain. Together they confirmed that the vulture was fine, but seemed trapped between the dense vegetation on the bank and the river water.

The Cinereous Vulture Natator observed from a distance. Left: trapped between the Tagus River and the vegetation on the bank. Right: drying its feathers after falling into the river. ©Paulo Monteiro/SPEA

A swimming vulture and an international rescue operation

In order to avoid any disturbing (and possibly unnecessary) interference and to check whether the parents would come to feed the young vulture, Paulo returned the next day and remained surveilling. The parents didn't come near, the young vulture frequently drank water from the Tagus and hopped around in the short space available to him, trying to stay in the shade. Growing restless from being trapped, at around 2pm, he took a chance and attempted a flight, but only managed to reach a few metres downstream. His physical condition and tiredness, and perhaps without any relief or thermals to help him take off, meant he couldn't get out of the trap he had voluntarily fallen into. Despite the failed flight, it showed good skills to swim back to the rocks on the bank.

This behaviour earned him the name Natator (swimmer, in Latin) and an international rescue operation. By boat, rangers from JEX and from the ICNF (the Portuguese Institute for Nature and Forest Conservation) and Paulo, from SPEA, managed to rescue the vulture, which was delivered to CERAS (Centre for the Study and Recovery of Wild Animals), managed by Quercus in Castelo Branco.

The movements of the Cinereous Vulture Natator between 14/08 and 13/09/2024 with frequent stops along the banks of the River Tagus. The yellow arrow indicates the rescue site.

Rescue operation of the Cinereous Vulture Natator. ©Agustin Ruano/AGM-JEx

Rehabilitatin for freedom

The young Natator entered CERAS malnourished, in a generally weak condition due to hunger and stress. He had slight injuries to his feet, probably due to the long time he had been on the rocks, and a bruised wing, with no bone damage, possibly due to falling into the water. Treating the effects of malnutrition, which included some neurological symptoms, was quite a lengthy process. But fortunately, this brave vulture made a full recovery. As if sensing his imminent return to the wild, on the eve of his release, he began practising his flights more diligently, proving he was ready.

During his stay at CERAS, Natator was able to count on good companions, also Cinereous Vultures, who helped him socialise and recover. Some of these birds, also juveniles from 2024 that recovered at CERAS for various reasons, will soon be transferred to acclimatise to the Douro International region. With no established territory or known origin, they will be key to strengthening the country's most fragile colony.

Returning to the wild

Natator's return to the wild took place last week, at an event attended by those who rescued and treated him (SPEA, JEx, ICNF, CERAS/Quercus), and the VCF, who coordinates the LIFE Aegypius Return project. The family that owns Herdade da Cubeira, where Natator hatched, was also present.

Enjoying freedom once again, Natator has remained in the Tejo Internacional Nature Park, fortunately without any risky stops by the water.