Where Do Swans Nest?


Swans create a huge nest with a diameter measured in feet rather than centimetres or inches, as is the case for most birds in the world. Mute Swan nests of two to three metres are not unusual. 

The main purpose of the swan’s nest is to accommodate the eggs in a reasonably secure location, where the male swan and female swan can guard and incubate the eggs.

From now on, we will frequently call the female swan, the pen, and the male swan, the cob – since these names are only meaningful if they refer to a breeding pair. (In the same way, the terms “mum” and “dad” could be meaningfully used to describe the woman and man in a couple that did have children.)

In this section we will look at how and where a pair of Mute Swans will build a nest and what they do to ensure that the fertilised eggs stand the best chance of bringing into fruition, more baby swans (cygnets) into the world.

Where Do Swans Build Their Nests?

Swans are primarily birds of freshwater and as a result about half of all Mute Swans nests are to be found in or by Stillwater. The rest are found round rivers, streams, etc... with less than 5% being located in coastal areas.

Those nests built around lakes and ponds, etc... can be sited on land (near the bank or on islands), whereas those built by birds living in running water tend to be nearly always on dry land. I assume this is because the water levels of rivers, streams and canals fluctuate more than those by stillwaters, so they need to allow more ‘leeway’ (in terms of height) to reduce the chance of the nest flooding.

When it comes to making the initial choice of where the nest should be built within the swan’s territory, it’s worked out as a collaboration between the pen and cob.

The cob usually makes the initial choice and starts to create the nest. At some point, the pen will inspect the nest site and construction and, if it’s not to her liking, he’ll find another spot and have to do better next time! Building more than just a couple of trial nests and settling on a fourth location is not unheard of.

What makes one particular spot better than another depends on a number of factors.

Firstly, the nest must have close access to shallow water, of around three feet, or less – so any food present can be easily accessed. The nest is often within feet of the water, the furthest I’ve know is about seventy five metres away from a river, in which the swans eventually brought up their family. There are some cases though, where birds have nested in such a position to consequently mean that they’ve had to cross a road to get the water – but this is unusual.

Secondly, there needs to be an abundance of natural food available for both the parents and young. (See section What Do Swans Eat and Drink?)

Thirdly - relatively undisturbed space. This applies both from human interference and attention from predators. They’re not likely to make a nest right near an otter holt or where people are regularly launching boats, etc... – unless, of course, there’s no other alternative. Some swans have been known to build their nest in the middle of a canal’s towpath! But, again, that’s the exception, rather than the rule.

Fourthly, a large amount of nest building materials needs to be very close by.

Finally, it needs to be well away from another pair of swans, ducks are tolerated, but other swans are definitely not. Most Mute Swan territories stretch for two to three kilometres in running water. Large stillwaters can accommodate more than one pair, but the lake needs to be large enough so the birds stay out of sight of each other for most of the time.

The main exception to this final point being at Abbotsbury Swannery, in Dorset. For at least six hundred years, there’s been a colony of Mute Swans living right next to a salt water fleet. They’re totally looked after – food, shelter, nesting materials, even immunisations are given. These are colonial birds.

The birds here nest within metres of each other and are quite able to live within such close proximity that would be almost impossible in a normal location where swans live. But there are still many territorial disputes between neighbours. The use of the term ‘territory’ in this case is a bit of a stretch, though. Since there are so many birds nesting in such a small area (there could be fifty pairs in an area less than the size of football pitch), each pair probably only claims ‘rights’ to a few metres from the nest.

The toleration of being so close to many other swans is probably to do with the extraordinary resources that are available to them that would not be there in the more common territorial situation. Also, many of the swans at Abbotsbury Swannery were actually hatched there from parents that also have ‘Abbotsbury history’. So, maybe, there’s a more complicated explanation involving some swans having ‘personalities’ being predisposed to being able to live in such a high density situation.

Once the nest’s site has been ‘agreed’ on by the pen and cob, the proper construction starts. Incidentally, assuming there are no problems with the nest site they choose and the breeding season is a successful one, it’s quite likely they will choose the same location again for next year’s breeding cycle.

For this reason, established pairs in a familiar territory are often earlier breeders than swans in a new territory. Swans new to an area have to go through the procedure of locating the ideal position for them and this will take time, hence delaying the nest building, often by a few weeks. As mentioned before in the section on Swans Breeding, swans new to each other and the territory often don’t breed at all in the first year.

Constructing The Nest

The pen will often lay the first egg of a clutch when the nest is still in its very early building stage – sometimes just a mound of vegetation about three feet in diameter, six inches deep, with a shallow depression in the centre to accommodate the egg.

From this point onwards, both swans will play their own part in building the nest. The material from which the nest is made must be very close by. These birds don’t fly in with material held in their bills, like many other species. The vegetation used to make the nest is often quite large and heavy, so it would be very difficult to carry it in their bills.

The actual material used includes things like large twigs/small branches, moss, bulrushes, reed mace, etc....sometimes, they even use bits of rubbish laying about, too.

What normally happens is that the cob will be standing by the nest and will reach out with his neck and pull off strands of plant material. He will then turn round and pass the object to the pen who then places it in the appropriate position on the nest. Although, I have seen the roles reversed – even with the same swan pair.

Swans normally construct their nest to have the following features:

A central cup/depression into which the eggs will lay. This is normally bedded down with some softer material (like grass and moss) and some down, from the pen, to cushion/support the eggs.

Gently sloping sides, to allow easy access to the nest for the new hatchlings and being able to push eggs, that have fallen from the central cup, back into the depression. 

High enough to not be swamped, if there’s a moderate increase in the water level. I have seen swans sense the water level rising and expediently work together to raise the level of the nest (and hence the all important egg cup) to stave off the impending disaster.

The final size of the nest is largely dependent on the amount and type of nearby material. Nests made out of largish twigs/small branches tend to be wider and higher than those made from grass and moss.

Also, if there is a lot of material around the nest site, this tends to make the final nest larger because the swans will be regularly adding to the nest during incubation. In fact, when you observe the swans on the nest, they are constantly shuffling the twigs, reed, etc... from place to place within the nest, presumably to get each one into the optimum spot.

 

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