No self-professed bird-lover should ever tire of ‘vismigging’, or watching avian migrations in action. This biannual event occurs when huge numbers of migratory birds follow established flyways to their breeding areas in spring, before returning along the same routes later in the year to overwinter.
Catching this fabulous phenomenon can be absolutely thrilling – especially when the travellers in question are large species such as storks and birds of prey.
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There are three main flyways, or superhighways in the sky, around the globe. Birds move between North and South America along the Americas flyway; the East Asia and Australasia flyway stretches from Alaska to Russia’s Taimyr Peninsula in the north, and to Australia and New Zealand in the south; while the African-Eurasian flyway is the route of choice between Africa and Europe or West Asia.
While all these flyways span a broad front, bottlenecks may occur where birds seek ways to avoid lengthy sea journeys. All migration is physically demanding, but ocean flights are harder for birds. Over land, those species with large wing surfaces, such as raptors and storks, save considerable energy by soaring and gliding. This flying technique takes advantage of a combination of updraughts (created by the land’s varied topography) and thermals (upwellings of warm air produced when the sun heats the Earth’s surface).
Once the birds reach the sea, though, these invisible elevators disappear. Which means, according to migration expert Simon Tonkin, that “obstacles such as mountain ranges serve as little more than speed bumps, while large stretches of open water operate like kryptonite”. As a result, many birds seek the shortest possible crossing over the sea.
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Where's the best place to see migrating birds?
At just 14km wide at its narrowest, the Strait of Gibraltar is the favoured crossing point between European and African landmasses. Countless species fly over the channel, which divides Spain from Morocco, including a plethora of raptors. Indeed, Gibraltar is one of the top five places in the world to encounter birds of prey on passage.
Which birds can you see there?
The variety and number of birds moving south for the autumn passage can be staggering. Between August and October, observers along the strait regularly record the migrations of 300,000 raptors, as well as 150,000 white and black storks. Of 28 raptor species, black kites are the most abundant, but there are high numbers of honey buzzards, short-toed eagles and Bonelli’s eagles.
Picking out the less numerous raptors tests your identification skills. These include griffon and Egyptian vultures, sparrowhawks and Montague’s harriers. And for any rarity seekers, successfully identifying a Rüppell’s vulture or greater spotted eagle should provide a thrill.
When is the best time to watch them?
Choosing precisely when and where to watch is a fine art, requiring a combination of experience and luck. The strait is prone to both westerly and easterly winds. If the winds are too strong the birds are reluctant to make the crossing, so amass on the Spanish side while waiting for conditions to improve. During helpful conditions, the birds appear to fly higher, but when the wind is blowing from an unfavourable direction they stay at lower altitudes, with the largest crossings often occurring after several days of strong winds. The best times for mass movements tend to be mid to late morning and mid to late afternoon.
Should you wish to take a break from craning your neck upwards, look lower down to enjoy the performance of the supporting cast. You’ll see colourful clouds of bee-eaters and different species of swifts slicing through the air, as they too prepare to head south for a winter break after the rigours of the breeding season.
Where are the best places to watch the migration?
Mirador del Estrecho, near Tarifa
While often busy with tourists, this is a good place to grab something to eat… while continuing to look upwards, of course.
Cazalla-Tarifa Watchpoint
A key watchpoint from which to see the drama unfold and a favourite of birders. Do bring a folding chair and plenty of water.
El Algarrobo Migration Watchpoint
Located just off the N340, this is usually staffed by volunteers to help you clinch those IDs.
Huerte Grande
Featuring a new education centre, wooded grounds and chalets, this eco-resort is an excellent place
to catch up with some of southern Spain’s other birds, while the migration continues overhead.
Strait of Gibraltar Bird Observatory
The observatory and information centre are strategically located on the south-western slopes of the Rock of Gibraltar, and offer panoramic views of both the strait and any birds making the crossing.
Discover more amazing wildlife from around the world
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- Gigantic iceberg breaks free in Antarctica, revealing ghostly mega-nest beneath
- “Hungry giants” filmed exploding out of the ocean in Alaska
Top image: white storks flying in Spain. Credit: Getty
