At the beginning of the 18th century and the first years of the 19th the herring gull was considered a rarity in Rome. So much so that it was worth noting the sighting of a single bird on the 7th of March 1912.
Translated from Atlante Degli Uccelli Nidificanti a Roma (Nesting Birds in Rome), Cignini and Zapparoli 1996.
We are probably all well aware of the presence of seagulls in Rome. They are large, noisy birds and can be seen and heard in any part of the city, especially along the river Tiber. But it was not always so. The first record of nesting gulls in the capital dates back to 1971. By 1996, 40 to 50 nests were recorded. Today there must be several hundred. The effect they have on the native bird populations is still being studied but they certainly present problems.
We have been particularly fortunate this year since a pair of gulls has nested and is raising a family on the tiled roof a mere 30 m across the road from our balcony and we have been able to keep a daily record of progress.
These gulls, the Mediterranean yellow-legged gull (Larus michahellis), are very closely related to the herring gull (Larus argentatus) of northern Europe. They are medium/large birds with white and grey plumage and black wing-tips. The beak and legs are yellow and their calls are instantly recognisable. They are scavengers rather than hunters and can be found in their hundreds around rubbish dumps, rivers, ploughed fields and fishing boats; in fact, anywhere where there might be something edible.
The gulls nest on the rooftop opposite is a fairly rudimentary shallow saucer constructed from grass and other plants. In March, the mother (it is impossible to distinguish between the sexes) produced three eggs and started serious sitting towards the end of the month. At intervals throughout the day the gulls partner came and took responsibility for brooding.
At the beginning of April three tiny chicks were seen with their wobbly heads reaching up out of the nest for food regurgitated by the parent. No drinking water is available on the roof so the chicks need to take all the water they need when they feed. After only three days the chicks left the nest and started walking about on the tiles. The parents were very busy and very vociferous and always on guard. The chicks were never left alone.
The gulls use a wide range of calls. At regular intervals the parent on the look out starts to call loudly with its head thrown back. Minutes later the other parent appears from on high and lands near the brood. An exchange of talking noises between the two adults follows. After a minute or two there is the changing of the guard and one flies away while the other starts to call the chicks, very gently, to feed. The chicks then rest while the parent remains on guard, and the whole scene is repeated at intervals of about half an hour.
The guarding parent is essential to the survival of the young. Hooded crows, the other great Roman scavengers, are always flying by in the hope of picking up a meal of seagull chick to take home to their own young. Gulls are usually colonial nesters and have hundreds of other gulls nearby to help protect them against marauders. In Rome, nesting singly on rooftops, this precious protection seems to be missing. However, when a crow approaches the parent gull flies into the air and lets out what must be an alarm call. Within minutes other gulls appear, presumably from other nesting sites in the vicinity. All is well. Crows will not readily attack gulls that are bigger and even more vicious than they are.
As the chicks grow and they do so visibly day by day the parent encourages them with gentle, sotto voce calls to explore the roof. Swifts, or rondoni, nest under the tiles and occasionally the gulls manage to intercept them as they return to their nests. The swift is rapidly torn to pieces and the young gulls fill themselves with fresh meat. The skeleton and wings are then promptly swallowed whole by the adult gull. Later in the season, when the swift nestlings are beginning to creep towards the entrance of their nests in anticipation of food from returning adults, these too are taken by the gulls and disposed of in a matter of minutes.
Swifts are one of the features of Roman summer skies as they scream around the rooftops. However, their population has been falling over the years, possibly due to the increase in the number of nesting gulls as well as atmospheric pollution. Perhaps as fishing and rubbish disposal techniques are improved and rivers are cleaned, the seagull population will diminish and the swift population will increase again. Meanwhile let those of us with a view over tiled rooftops enjoy the family life of Roman seagulls. We can learn a lot from them.