In the past week about 20 swans have died mysteriously on the lakes, not counting the three I spotted today. Out of only 50 that is an unusually high percentage, and the numbers are climbing. This has put me in a Sherlock mode: I want to know what is being done. The information has been contradicting at times, and scattered ranging from "maybe they are just taking a nap," to "it is only natural that the weak succumb".
Taking a nap..
My concern for the water birds started already last winter, when I got in touch with the animal control lady to hear what I could do to help. And it turned out that there is a useful set of guidelines, but allow me to introduce you to the City's politics: the decision is made on the highest level that these guidelines not be made available to the general public. On the grounds that advising on feeding would only encourage more feeding, and the best thing for the birds would be to leave the lakes altogether during winter. But there are also no signs discouraging feeding. No information available whatsoever, and I find that so incredibly idiotic! Since when was knowledge a bad thing? And why are we being treated like children? The animal control lady, employed by the City, was not willing to admit that this may not have been the ideal approach. She did, however, share some of the hush-hush information.
The hush-hush information:
White bread is for birds what popcorn is to humans: empty fillings that pass through the digestive system very fast. The best diet is whole grains, preferably served on the rocks (as on the icy part of the lake), and not directly in the water, as this could lead to bacteria in the water and suck out the oxygen. The bad thing about feeding the swans during the winter is the fear that it will attract the weaker birds not strong enough to make it on their own, and that they would transmit diseases to the healthy ones. Classic in-the-wild swan behavior allows for switching to the slow burner, lying completely still and not spending energy chasing food, but simply tapping from the reserves for at period of up to two months. (End of hush-hush information)
The reality:
Switching to the slow burner is not an option for the city swans. People walk on the ice, we continue our feeding and on occasions like New Years Evening we have insane fireworks and other stressful activities. There is no place to rest and save the batteries. Feeding must be kept up or cut off entirely.
The lake in the end near the Osterbro side is separated from the others. And because the nearby hospital filters out water here it is warmer than the other lakes, and that has not gone unnoticed with the water birds. The water holes are bigger, and since they have been fed all year, staying put is not necessarily a symptom of weakness. The birds have simply gathered in the warmest and friendliest water in Copenhagen. What kind of survivor leaves that behind?

The swans last year at this time.
Off the record, a.k.a. the truth:
I have talked to several experts by now, and none of them wants to go on record with their opinions, as quite a few of them contradict that of the City's. Not having signs with guidelines is not surprisingly one of them. In the lakes outside the city where the swans do switch to the slow burner, people throw rocks and sticks at them, and send out dogs (I know, people are idiots sometimes, the more reason to educate them), to check if the swans are still alive. A simple sign advising them not to would fix that. We have been told repeatedly that feeding the swans is not a great idea, so more (including me) have stopped. And now the swans are starving, and several of them are underweight. I can't tell you how fast I ran to feed them once I learned about this.

White bread, formerly accused of being popcorn, is far better than nothing because it will get them through the winter, and later they can seek out the minerals and other things they need to balance the diet. We should feed them white bread and rye bread (this coming from an expert and non-city payee, mind you).
Death on the lakes:
Several ministries are involved by now. One have autopsied a number of the dead swans to successfully rule out the bird flu. Another department is currently looking into other causes. I wanted to know if well-meaning civilians could have fed the birds something to cause this, but short of poison there is nothing we can feed them that will kill off so many birds at once. So far the mystery remains, and just today I spotted another three dead swans. At this pace there may not be any feeding signs necessary by next winter. That, my dear Watson is elementary.