Urban kestrels in Rotterdam: three years of rooftop watching

The Müller grain elevator on the Waalhaven has been empty since 2017. The cranes are rusted, the loading galleries are fenced off, and pigeons own the upper floors. But every February, a pair of kestrels arrives and claims the concrete ledge on the south-facing wall of the main tower, about forty metres up. I've watched them there every season since 2023.

This April they fledged five chicks. I counted them for three consecutive mornings from the embankment across the water, watching them take their first hovering attempts over the dock basin. One kept drifting sideways in the harbour wind, compensating with frantic wingbeats before landing on a bollard. By day four they were ranging further south toward Charlois.

Why urban sites work

The standard picture of a kestrel is over farmland — hovering above a roadside verge, dropping onto a vole in a ditch. That's where most of the population hunts, and that's where I spent my first two seasons. But Rotterdam has been quietly building up a respectable urban kestrel population over the past decade, for a few reasons that took me some time to understand.

First, the heat island effect keeps grass shorter and prey more exposed on south-facing industrial rooftops and rail corridors through winter. A kestrel that would otherwise have to move south stays put if there are enough voles in the harbour zone. Second, there are almost no nest sites in the polder — kestrels need cavities or ledges and the agricultural landscape offers almost nothing. A city with hundreds of old buildings, unoccupied towers, and rail bridges is comparatively rich in options.

Third, and this one surprised me: urban kestrels appear to habituate to disturbance faster than rural birds. The pair at Müller tolerates the 25 ferry running thirty metres below the nest ledge. A rural bird would flush from that repeatedly.

Three years of data

Photographing from the embankment

The Waalhaven embankment gives a clean sightline to the nest ledge at roughly the same elevation. I'm typically at 400-500m distance, which means the 600mm end of the Sigma is working hard. At that range in the low morning light of April, I'm shooting at f/6.3, ISO 3200, 1/1600s — fast enough to freeze the hover, slow enough to keep the noise manageable.

The challenge is the harbour haze. By 10am in any decent weather, heat shimmer off the water surface starts breaking up detail at that distance. I've learned to be there at first light — 06:30 in April — and accept that the session is probably over by 09:00.

There's something strange about watching a wild raptor through a 600mm lens against a backdrop of container cranes and LNG tankers. It doesn't stop being a kestrel. If anything the contrast makes the hovering more striking — that absolute stillness relative to the ground while everything around it moves.

Other Rotterdam sites

Müller is the most reliable, but I've logged kestrels at four other sites in the city in the last three years:

• Blaaktoren (the "Pencil" tower): Occasional perch. Never confirmed nesting, probably too much disturbance from the terrace.
• NS Rail bridge, Hofplein: Pair present in 2024, no confirmed nest. Could be using the abutment cavity.
• Katendrecht harbourside: Single bird, adult female, hunting the grass strip along the water in winter 2025.
• Feyenoord stadium roof: One record of a male perching on the roof antenna in March 2026. Almost certainly dispersing from the Müller nest.

If you're in Rotterdam and want to check the Müller site yourself, the best viewpoint is the eastern end of the Waalhavenweg, about 200m past the swing bridge. You'll need a scope or at least 400mm to see the nest ledge properly.