Simply put, this means that the mathematical odds that a bird will get eaten are smaller when the flock is larger. This is accomplished by growing in a direction that optimizes the distance between nearby roots, thereby increasing their chance of exploiting untapped nutrient reserves.  Airlines have also used ant-based routing in assigning aircraft arrivals to airport gates. The group coordination that emerges is often just a consequence of the way individuals in the colony interact. Other cockroaches will follow these trails to discover sources of food and water, and also discover where other cockroaches are hiding. Selection of the best food source is achieved by ants following two simple rules. This dance conveys information about the quality, direction, and distance of the new site. Some species form surface swarms during the day for feeding and reproductive purposes even though such behaviour is dangerous because it makes them extremely vulnerable to predators.  The genus Culicoides also known as biting midges have displayed swarming behavior which can cause predatory confusion.  Researchers have found that cooperation at the colony level is largely self-organized. Whereas one large robot may fail and ruin a mission, a swarm can continue even if several robots fail. Even though the ambush may have several points of attack on the enemy, the guerillas withdraw when they either have inflicted adequate damage, or when they are endangered. It then searches in the problem space through successive generations using stochastic optimization to find the best solutions. A large flock of starlings swoops off the coast of Brighton on Feb. 22, 2011, in Brighton, England. As a culture, the Celts had a strong connection with birds believing that they held prophetic knowledge. , A collection of people can also exhibit swarm behaviour, such as pedestrians or soldiers swarming the parapets[dubious – discuss]. In North America they make massive southward migrations starting in August until the first frost. , The concept of self-propelled particles (SPP) was introduced in 1995 by Tamás Vicsek et al. When disturbed, a swarm scatters, and some individuals have even been observed to moult instantaneously, leaving the exuvia behind as a decoy. Slightly further away, in the "zone of alignment", the focal animal will seek to align its direction of motion with its neighbours. Regardless of the size of the murmuration, all the birds seem to be connected to the same network. More pheromone is laid for higher quality food sources.  As a term, swarming is applied particularly to insects, but can also be applied to any other entity or animal that exhibits swarm behaviour. In Cologne, Germany, two biologists from the University of Leeds demonstrated flock like behaviour in humans. Swarms densities were about one million copepods per cubic metre. It is important to know which bird you saw so you can have a clear picture about the meaning of the event you have experienced. Some copepods have extremely fast escape responses when a predator is sensed and can jump with high speed over a few millimetres (see animated image below). Ants are behaviourally unsophisticated; collectively they perform complex tasks. Military swarming is a behaviour where autonomous or partially autonomous units of action attack an enemy from several different directions and then regroup.  Understanding how humans interact in crowds is important if crowd management is to effectively avoid casualties at football grounds, music concerts and subway stations.. If she can convince others they may take off and check the site she found.