Refuse areas are the perfect breeding ground for all kinds of pests.
The large amounts of ammonia in the slurry become breeding ground for bacteria, which turn it into acid.
It is now more famous for the Seal Reserve, a breeding ground for thousands of cape fur seals.
In 1557, however, a great flood caused the Tiber to change its course, so that it no longer flowed under the walls of the castle, but some half a mile farther west; and its old bed (Fiume Morto) has ever since then served as a breeding ground for the malarial mosquito (Anopheles claviger).
The song and insectivorous birds - thrushes, flycatchers, vireos and woodpeckers - of this latitude, are well represented, and the high plateaus (particularly the Pocono plateau) have especial ornithological interest as the tarrying-places, during the migratory seasons, of many species of birds whose natural breeding ground is much farther north.