A kestrel is praying above the meadows of the Wormer and Jisperveld. Standing still in the air, he looks down at the grass. It’s a male looking for a mouse. Suddenly the bird dives down into the grass. After a minute he shoots into the air again, with empty legs. Wrong.
We sail through the ditches with guide Jaap van het Kaar. We got on at the Poelboerderij. “Kestrels are also called piss-watchers.” The kestrel is already in the air again. “They can see ultraviolet light that allows them to track mice indirectly. Mice always leave a urine trail behind them. The ultraviolet light from that only has to follow the kestrel to get to a mouse.”
Natural North Holland – Jisperveld – NH News
That sounds easy, but it isn’t. Anyone who remembers how much energy it takes to tread water knows roughly what the Kestrel feels when it has to ‘stand still’ in the air for a few minutes. In addition, it is not always a hit. “Mice keep a close eye on the sky and dart away as soon as they see a shadow.”
We continue sailing through the polder. “Every island has a name”, says Jaap. “It is impossible for regular livestock farmers to earn a living here. The cows always have to get in and out of the boat. That is why Natuurmonumenten has a large deep stable here and the interest lies mainly with the meadow birds.”
Those meadow birds, the godwits, redshanks and other waders are not visible now. They are their wintering ground in Africa. There are lapwings. They dart through the air. Just like starlings and geese.
Back in the visitor center De Poelboerderij we warm up again with a hot chocolate and a filled cake. We marvel at the aquariums. Roach, perch and other fish are easier to see than in nature. “The water here is dark with muck,” says Jaap. The fish is there, but you can’t see it.”
Excursions are regularly organized from the poelboerderij in the Wormer and Jisperveld. Can you see the kestrels at work yourself!