Life on the bridges
The Chapel Bridge is home to a variety of creatures. Its open wooden structure provides shelter for some pretty unusual species such as the Daubenton’s bat, the Alpine swift and the bridge spider or grey cross spider.
You need patience, keen eyes and sharp ears to spot them: discover which animals call the Chapel Bridge their home and who lives in the cracks in the piers.
With gulls and lichen on its roof and algae and lake trout down below in the water, the Chapel Bridge contributes hugely to urban biodiversity.
Bats live on the underside of the bridge deck – largely unnoticed by passers-by – and the Water Tower houses the largest colony of Alpine swifts in the whole of the canton. There are plenty of insects here for all. And if you look over the parapet, you’re likely to spot the odd lake trout or a tufted duck diving.
The elaborate aerial displays that Alpine swifts perform on fine summer evenings are legendary. With their typical trilling call, they circle the Water Tower in the early hours of the evening, soaring to ever greater heights and swooping back down again. This is the colony’s roosting ritual. Perfectly adapted to life in the air, Alpine swifts remain faithful to their nest site and to their mate for life. Breeding pairs have nested in the roof space of the Water Tower for decades. Most of the nesting sites are in the upper, wooden part of the tower, directly behind the outer wall.
The birds return from their winter quarters in tropical Africa in April and herald the start of spring in Lucerne. As hunters of flying insects, they can only find enough food here in summer. Whether feeding or sleeping, the animals are able to maintain all their bodily functions during their endurance flight. The Alpine swift is on the “Red List” as a potentially endangered species.
swifts have been breeding in the Water Tower
nest here every year
are laid by the female in mid-May
is the incubation time for the eggs
is the time it takes for the nestlings to fledge
… colony of Alpine swifts in the whole of Canton Lucerne breeds in the Water Tower.
Gulls, ducks, swans and grebes: thousands of waterbirds winter every year in the heart of the city of Lucerne. In the summer there are just a few hundred. This fluctuation has to do with waterbirds’ migratory behaviour. Pondweeds and stoneworts thrive in the clear water, which is only a few metres deep, and, together with banks of zebra mussels, are the source of food for the waterbirds.
From October to March, tufted and diving ducks can often be spotted diving for zebra mussels in the Reuss near the Water Tower and resting behind it, where they are protected from the current. There are dozens of swans along the section of the Reuss between the Water Tower and Jesuit Square (Jesuitenplatz), as well as common coots and mallards, while black-headed gulls sit all in a row along the roof of the Chapel Bridge – interrupted here and there by a mew gull or a yellow-legged gull.
The quintessential wild duck
With a typical crest or tuft of feathers on the crown of its head
The second most abundant duck species in winter
A wintering guest from Spain
The largest native waterbird
The so-called “laughing gull” provides amusement with its aerial acrobatics
Larger and stronger than the black-headed gull
The only large gull to breed in Switzerland
The second most abundant breeding waterbird in Switzerland
The largest of all dabbling and diving ducks
Well-intentioned but counterproductive
Feeding the flying urban dwellers is not very helpful, and in the long run tends to be harmful to them.
Animal watching is fun and provides an opportunity to gain an insight into their behaviour. However, waterbirds are not dependent on us feeding them. On the contrary: feeding – however well-intentioned – encourages the transmission of diseases. Rats and pigeons also eat food left for the birds and then, as a consequence, multiply uncontrollably.
When they feed pigeons, animal lovers are doing the objects of their affection a harmful disservice. Feeding them allows them to reproduce more prolifically and they end up living closer together. Diseases and parasites can spread more easily, which has a negative impact on the health of the animals. The city’s “Stadttauben Luzern” project calls on the public to refrain from feeding feral pigeons. The aim is to have fewer but healthier pigeons living in the city of Lucerne.
The biodiversity on the historic wooden bridges does not please everyone
Bird or spider droppings on the artworks, stone or wood can damage their surface. And if there is a fire, spiders’ webs can act as an accelerant.
The bridge spider or grey cross spider is nocturnal and stays in its hiding place during the day. What are visible, however, are their large, spiral, wheel-shaped webs. It is a common and widespread spider species that tends to live on bridges near water.
They are very sociable. The bridge spider likes to build its web next to light sources, such as the lights on the Chapel Bridge, which help to attract nocturnal insects. Read about who is responsible for clearing away the webs and why it has to be done.
There is also a lot of life under the wooden bridges, but it goes largely unnoticed by passers-by. It takes a keen pair of eyes to spot fish and bats.
A specimen of any of the 35 fish species that are found in Lake Lucerne could swim under the Chapel Bridge at any time. Some of these species are endangered or even threatened with extinction. Like the common nase, whose population has declined drastically in recent decades.
Another highly endangered species is the native lake trout. They do not return to their natal waters to reproduce, as is usually the case, but swim downstream into the Reuss to spawn – a local peculiarity. If you have a trained eye, lake trout can be spotted breeding in November and December.
Threatened with extinction
Highly endangered
Vulnerable
Potentially endangered
During the day they are at rest in their hiding place under the Chapel Bridge. In the evening they fly over the surface of the Reuss hunting. Despite the noise of feet pounding overhead, Daubenton’s bats raise their young here summer in, summer out. Bats use the same roosts over and over again, where they sleep upside down. Despite its small size, the Daubenton’s bat, also known as the “water bat”, has a good appetite – it can eat up to 500 mosquitoes an hour.
It finds its prey using ultrasonic echolocation. In other words, it continuously emits signals that are inaudible to humans. The signals hit potential prey and return as echoes. The Daubenton’s bat, like all bat species, is protected by law and considered endangered.gefährdet. Find out here who is responsible for their protection and why this is important.