question: what stops larger predator birds from annihilating pigeon and seagull populations in cities?
comment: They absolutely do hunt them, I've seen it many times. But, the population and reproduction success of pigeons is far higher than hawks and falcons.
passages: Long-term reduction of feral pigeon populations can be achieved by restricting food supply, which in turn involves legislation and litter (garbage) control. Some cities have deliberately established favorable nesting places for pigeons—nesting places that can easily be reached by city workers who regularly remove eggs, thereby limiting their reproductive success. In addition, pigeon populations may be reduced by bird control systems that successfully reduce nesting sites.
  
  Section::::Population control.:Predators.
   Section::::City squares famous for pigeons.
  
  Many city squares have large pigeon populations, such as Washington Square Park in New York City, George Square in Glasgow, the Piazza San Marco in Venice, Dam Square in Amsterdam, The Gateway of India and Kabutarkhana in Mumbai and (prior to 2000) Trafalgar Square in London.
  
  Section::::Population control.
   Since the expansion of the human population and urbanization, there have been numerous extinctions of birds. Extinctions threaten nearly 12% of bird species, but this does not account for an additional 12% of species located in small geographical ranges where human actions rapidly destroy habitats.
  
  Due to pressures from humans and the environment, birds have unique features that permit adaptations to changing conditions.
   Urban wildlife can be found at any latitude that supports human dwellings - the list of animals that will search human trash within settlements runs from tropical monkeys to polar bears in the Arctic.
  
  Different types of urban areas support different kinds of wildlife. One general feature of bird species that adapt well to urban environments is they tend to be the species with bigger brains, perhaps allowing them to be more adaptable to the changeable urban environment.
  
  Section::::Evolution.
   Potential ecological impacts include the transmission of a frequently fatal disease in many bird species worldwide, not just pigeons. Overseas it has infected raptors, pheasants, swans and cockatoos. In Australia, the virus has predominantly infected introduced pigeons but one native species has been diagnosed with the disease - a collared sparrowhawk which presumably ate a diseased introduced pigeon. With introduced pigeons so widely distributed, scientists are concerned about the further spread to native birds in Australia and nearby Papua New Guinea, which together house the world’s most diverse native pigeon and dove fauna - a quarter of the world’s total.
   Peregrine falcons, which are also originally cliff dwellers, have also adapted to the skyscrapers of large cities and often feed exclusively on rock pigeons. Some cities actively encourage this through falcon breeding programs. Projects include Unibase Falcon Project and the Victorian Peregrine Project.
  
  Larger birds of prey occasionally take advantage of this population as well. In New York City, the abundance of pigeons (and other small animals) has created such a conducive environment for predators that the red-tailed hawk has begun to return in very small numbers, including the notable Pale Male.
  
  Section::::Population control.:Poison.
   In 2008, the global population was fewer than 2200 individuals, which is a reduction from approximately 5000 in the 1980s. In Malaysia, population counts decreased steadily from over 100 individuals in 1984 to less than 10 by 2005 (by over 90%), so that the population here faces local extinction. Of the current world population estimate, there are probably about 1600 individuals in Sumatra, less than 500 on Java, and less than 100 on the southeast Asian mainland. The Cambodian population is very small, numbering 100–150 individuals; and although it may be relatively stable, rapid declines are expected if serious threats persist. Due to the substantial population declines across its range, the milky stork's population status was elevated to Endangered from Vulnerable in 2013 by the IUCN.
   Bird–skyscraper collisions
  
  Bird–skyscraper collisions are a problem in urban areas. Several major cities like Toronto in Canada and New York City in the United States have programs to abate this, such as Toronto's Fatal Light Awareness Program (FLAP) and New York City's Lights Out New York, a program of New York City Audubon an environmental organization. According to FLAP, between one and nine million birds die each year in the city from hitting skyscrapers due to mistaking reflective windows for open sky, or being drawn to lights at night.
   From an ecological perspective, raptor populations in urban areas are highly beneficial. Compared with Europe, where pigeon populations have exploded to the point they are both a tourist attraction and a public nuisance. Pigeons' faeces are highly acidic, corroding historic buildings and stone statues and rusting bridge ironwork. In the United States, falcon and other raptors are in numbers high enough to ward off pigeon nest building in major highrises.
  
  Section::::Cultural significance.
   BULLET::::- Society Parakeet
  
  1780
  
  BULLET::::- Bay Thrush
  
  BULLET::::- Mysterious Starling
  
  BULLET::::- Rodriguez Solitaire
  
  1793
  
  BULLET::::- Oceanic Eclectus Parrot
  
  Section::::19th century.
  
  c. 1800
  
  BULLET::::- Amsterdam Island Duck
  
  BULLET::::- Dominican Green-and-yellow Macaw
  
  BULLET::::- Painted Vulture
  
  BULLET::::- Reunion Ring-necked Parakeet
  
  BULLET::::- Rodrigues Parrot
  
  BULLET::::- Moorea Sandpiper
  
  BULLET::::- Tahiti Sandpiper
  
  BULLET::::- Tanna Ground Dove
  
  BULLET::::- Tonga Tabu Tahiti Flycatcher (subsp.)
  
  1801
  
  BULLET::::- Norfolk Pigeon
  
  1825
  
  BULLET::::- Oahu ‘Ōma’o (subsp.), a thrush
  
  1826
  
  BULLET::::- Pigeon Hollandaise
  
  1827
  
  BULLET::::- Kusaie Mountain Starling
  
  1828
  
  BULLET::::- Kittlitz's Thrush
  
  1830
  
  BULLET::::- Bonin Grosbeak
  
  BULLET::::- Kangaroo Island Emu (subsp.)
  
  BULLET::::- White Gallinule
  
  1837
  
  BULLET::::- Oahu O-O,
  
  1840
  
  BULLET::::- Dieffenbach's Rail
   The most commonly cited human threat to birds is habitat loss. Other threats include overhunting, accidental mortality due to collisions with buildings or vehicles, long-line fishing bycatch, pollution (including oil spills and pesticide use), competition and predation from nonnative invasive species, and climate change.
   However, when the fruit crop of Til and Azores Laurel is poor, large numbers of pigeons may leave the forest to feed on cabbage, flowering cherries and vine shoots. Competition for food with rats can be significant in parts of the island.
  
  Section::::Distribution and habitat.
   For seabirds, the location of colonies on islands, which are inaccessible to terrestrial predators, is an obvious advantage. Islands where terrestrial predators have arrived in the form of rats, cats, foxes, etc., have devastated island seabird colonies. One well-studied case of this phenomenon has been the effect on common murre colonies on islands in Alaska, where foxes were introduced for fur farming.
  
  Section::::Human use.
   Governments of Canada and the United States have recently introduced legislation to make new and existing buildings bird friendly. Examples include Toronto's Bird-Friendly Development Guidelines that requires new buildings to be bird friendly, Chicago's Design Guide For Bird-Safe Buildings New Construction And Renovation, New York's Bird Friendly-Buildings Act that will require new and existing building be bird friendly effective Jan 1, 2012. On the Federal level the Federal Bird-Safe Buildings Act of 2011 calls for each public building constructed, acquired, or altered by the General Services Administration (GSA) to incorporate bird-safe building materials and design features. The legislation would require GSA to take similar actions on existing buildings, where practicable.
   Colony-nesting birds have been used by humans as a source of food in the form of eggs and meat, down for bedding, feathers for quill pens, and guano for fertilizer. Over-exploitation can be devastating to a colony, or even to an entire population of a colonial species. For example, there was once a large seabird known as the great auk, which nested in colonies in the North Atlantic. Eggs and birds were used for a variety of purposes. Beginning in the 16th century, seafarers took the birds in especially great numbers to fill ships' larders, and by the mid-19th century, the great auk was extinct. Likewise, the short-tailed albatross of the North Pacific was heavily harvested at what seems to have been its primary colony on Torishima Island. Millions of birds were killed in less than two decades at the end of the 19th century. The species survives, though endangered. In North America, the extermination of the highly gregarious passenger pigeon has been well documented. The birds were hunted as if inexhaustible. Case in point: in 1871, in Wisconsin, an estimated 136 million pigeons nested in a dense congregation over a wide area; thousands of people were drawn to hunt the birds, shipping the squab to market by rail. The passenger pigeon is a famous example of a familiar bird going extinct in modern times.
   Large populations can form, however birds disperse and numbers decline following extended periods of extreme drought. After rain, when food supplies increase, there is often a slow recovery in numbers due to local breeding.
  
  Section::::Behaviour.:Food and foraging.
  
  Spinifex pigeons are unique among many other desert birds in that they are sedentary arid spinifex habitat specialists. They are capable of enduring extreme conditions and the availability of drought-resistant seed plants varies greatly with seasonal conditions, often declining substantially during periods of extended drought.
   BULLET::::- Namaqua dove, unsuccessfully introduced to New Zealand and Australia
  
  BULLET::::- Emerald dove, unsuccessfully introduced to the Hawaiian Islands and perhaps New Zealand
  
  BULLET::::- Common bronzewing, unsuccessfully introduced to New Zealand and the Hawaiian Islands
  
  BULLET::::- Crested pigeon, possibly successfully introduced to Kangaroo Island; unsuccessfully introduced to the Hawaiian Islands, New Zealand, Europe and the United States
  
  BULLET::::- Partridge pigeon, unsuccessfully introduced to the Hawaiian Islands and perhaps New Zealand
  
  BULLET::::- Spinifex pigeon, unsuccessfully introduced to the Hawaiian Islands and Kangaroo Island
  
  BULLET::::- White-tipped dove, unsuccessfully introduced to the Hawaiian Islands
   Racing pigeon owners in Great Britain have said for many years that Eurasian sparrowhawks and peregrine falcons ""cause serious and escalating losses"" of pigeons and some have called for these birds of prey to be killed or removed from areas surrounding homing pigeon lofts.
   BULLET::::- In the United Kingdom, griffon vultures were made extinct at some point before the 1600s. Occasional vagrants appear in the UK, and in 2000 a vulture took up residence on the Channel Island of Guernsey.
  
  BULLET::::- In Cyprus, there is an unsustainable colony of fewer than 30 birds (2016) at Episkopi, in the south of the island.
   The greatest threats to Columbidae species is habitat loss and degradation, hunting by man, and alien predators. Other threats include disease and possible competition from introduced species. Large flocks of Ducula are mobile and able to exploit large areas for food sources, but are nevertheless vulnerable to large scale loss of forests.
  
  Pigeons are exploited by man for food and sport. Hunting of "D. spillorhoa" on the Australian mainland has reduced populations. Hunting for food remains a problem in Asia and the Pacific as Columbidae provides a palatable source of protein. Historically, human habitation has been associated with extinctions.
   Alongside human activities, natural enemies include cheetahs, leopards and lions, which all sometimes prey on this species. Eggs may be also at risk of predation by African fish eagles. At one colony in Kisumu, Kenya, approximately 61% of eggs counted between all nests hatched and 38% were predated by fish eagles. The success rate of fledglings was only 0.33 young per nest. However, increased egg predation by fish eagles has been reported to be linked to decline in fish stocks in the Winam Gulf.
  
  Section::::In culture or relationships to humans.
   There is ample reason for the concerns of pigeons damaging property, due to their size and proximity to people and their dwellings. Pigeons often cause significant pollution with their droppings, though there is little evidence of them driving out other bird species. Pigeons are labeled an invasive species in North America by the USDA.
   Feral pigeons often only have small populations within cities. For example, the breeding population of feral pigeons in Sheffield, England, has been estimated at only 12,130 individuals. Despite this, feral pigeons usually reach their highest densities in the central portions of cities, so they are frequently encountered by people, which may lead to conflict.
  
  Feral pigeons are widely considered pests, and are known to act as reservoirs and vectors of multiple human and livestock diseases. It is rare that a pigeon will transmit a disease to humans due to their immune system.
   Section::::Problems and methods of control.:Other methods.
  
  Other methods have been used with little or limited success. Lasers have been used successfully to remove large flocks of birds from roost structures in urban areas, but success in keeping crows off roosts has been short-lived. Homeowners can reduce the presence of crows by keeping trash stored in containers, feeding pets indoors, and hanging tin pie-pans or reflective gazing globes around garden areas.
  
  Section::::As food.
   BULLET::::- Yellow-browed warbler - "Phylloscopus inornatus" - ("")
  
  BULLET::::- Hume's warbler - "Phylloscopus humei" - ("") (V)
  
  BULLET::::- Pallas's leaf warbler - "Phylloscopus proregulus" - ("") (V)
  
  BULLET::::- Radde's warbler - "Phylloscopus schwarzi" - ("") (V)
  
  BULLET::::- Dusky warbler - "Phylloscopus fuscatus" - ("") (V)
  
  BULLET::::- Willow warbler - "Phylloscopus trochilus" - ("")
  
  BULLET::::- Common chiffchaff - "Phylloscopus collybita" - ("")
  
  BULLET::::- Iberian chiffchaff - "Phylloscopus brehmii" - ("")
  
  BULLET::::- Eastern crowned warbler - "Phylloscopus coronatus" (V)
  
  BULLET::::- Greenish warbler - "Phylloscopus trochiloides" - ("") (V)
  
  BULLET::::- Two-barred warbler - "Phylloscopus plumbeitarsus" - ("") (V)
  
presuppositions: Something prevents predator birds from annihilating pigeon and seagull populations in cities.
corrections: Predator birds do hunt pigeons and seagulls in cities but the population of pigeons is far higher than predator birds.
raw_presuppositions: Something prevents predator birds from annihilating pigeon and seagull populations in cities. Predator birds are stopped from annihilating pigeon and seagull populations in cities.
raw_corrections: Predator birds do hunt pigeons and seagulls in cities but the population of pigeons is far higher than predator birds. Predator birds do hunt pigeons and seagulls in cities but the population of pigeons is far higher than predator birds.