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Birds that feed in flocks commonly retire together into roosts. The reasons for roosting communally are not always obvious, but there are some likely benefits.

In winter especially, it is important for birds to keep warm at night and conserve precious food reserves. One way to do this is to find a sheltered roost. Solitary roosters shelter in  dense vegetation or enter a cavity - horned larks dig holes in the ground and ptarmigan burrow into snow banks - but the effect of sheltering is magnified by several birds huddling together in the roosts, as wrens, swifts, brown creepers, bluebirds, and anis do. Body contact reduces the surface area exposed to the cold air, so the birds keep each other warm. Two kinglets huddling together were found to  reduce their heat losses by a quarter and three together saved a third of their heat.

The second possible benefit of communal roosts is that they act as “information centers.” During the day, parties of birds will have spread out to forage over a very large area. When they return in the evening some will have fed well, but others may have found little to eat. Some investigators have observed that when the birds set out  again next morning, those birds that did not feed well on the previous day appear to follow those that did. The behavior of common and lesser kestrels may illustrate different feeding behaviors of similar birds with different roosting habits. The common kestrel hunts vertebrate animals in a small, familiar hunting ground, whereas the very similar lesser kestrel feeds on insects over a large area. The common kestrel roosts and  hunts alone, but the lesser kestrel roosts and hunts in flocks, possibly so one bird can learn from others where to find insect swarms.

Finally, there is safety in numbers at communal roosts since there will always be a few birds awake at any given moment to give the alarm. But this increased protection is partially counteracted by the fact that mass roosts attract predators and are especially  vulnerable if they are on the ground. Even those in trees can be attacked by birds of prey. The birds on the edge are at greatest risk since predators find it easier to catch small birds perching at the margins of the roost.

The organization that today is known as the Bank of America did start out in America, but under quite a different name. Italian American A.P. Giannini established this bank on October 17, 1904, in a renovated saloon in San Francisco’s Italian community of North Beach under the name Bank of Italy, with immigrants and first-time bank customers comprising the majority of his first customers. During its development, Giannini’s bank survived major crises in the form of a natural disaster and a major economic upheaval that not all other banks were able to overcome.

One major test for Giannini’s bank occurred on April 18, 1906, when a massive earthquake struck San Francisco, followed by a raging fire that destroyed much of the city. Giannini obtained two wagons and teams of horses, filled the wagons with the bank’s reserves, mostly in the form of gold, covered the reserves with crates of oranges, and escaped from the chaos of the city with his clients’ funds protected. In the aftermath of the disaster, Giannini’s bank was the first to resume operations. Unable to install the bank in a proper office setting, Giannini opened up shop on the Washington Street Wharf on a makeshift desk created from boards and barrels.

In the period following the 1906 fire, the Bank of Italy continued to prosper and expand. By 1918 there were twenty-four branches of the Bank of Italy, and by 1928 Giannini had acquired numerous other banks, including a Bank of America located in New York City. In 1930 he consolidated all the branches of the Bank of Italy, the Bank of America in New York City, and another Bank of America that he had formed in California into the Bank of America National Trust and Savings Association.

A second major crisis for the bank occurred during the Great Depression of the 1930s. Although Giannini had already retired prior to the darkest days of the Depression, he became incensed when his successor began selling off banks during the bad economic times. Giannini resumed leadership of the bank at the age of sixty-two. Under Giannini’s leadership, the bank weathered the storm of the Depression and subsequently moved into a phase of overseas development.

The changing profile of a city in the United States is apparent in the shifting definitions used by the United States Bureau of the Census. In 1870 the census officially distinguished the nation's “urban” from its “rural” population for the first  time. “Urban population” was defined as persons living in towns of 8,000 inhabitants  or more. But after 1900 it meant persons living in incorporated places having 2,500 or more inhabitants.

Then, in 1950 the Census Bureau radically changed its definition of “urban” to take account of the new vagueness of city boundaries. In addition to persons living in incorporated units of 2,500 or more, the census now included those who lived in  unincorporated units of that size, and also all persons living in the densely settled urban fringe, including both incorporated and unincorporated areas located around cities of 50,000 inhabitants or more. Each such unit, conceived as an integrated economic and social unit with a large population nucleus, was named a Standard Metropolitan Statistical Area (SMSA).

 Each SMSA would contain at least one central city with 50,000 inhabitants or more or  two cities having shared boundaries and constituting, for general economic and social purposes, a single community with a combined population of at least 50,000, the smaller of which must have a population of at least 15,000. Such an area included the county in which the central city is located, and adjacent counties that are found to  be metropolitan in character and economically and socially integrated with the county of the central city. By 1970, about two-thirds of the population of the United States was living in these urbanized areas, and of that figure more than half were living outside the central cities.

While the Census Bureau and the United States government used the term SMSA,  by 1969 there were 233 of them, social scientists were also using new terms to describe the elusive, vaguely defined areas reaching out from what used to be simple “towns” and “cities”. A host of terms came into use: “metropolitan regions,” “polynucleated population groups,” “conurbations,” “metropolitan clusters,” “megalopolises,” and so on.

It is commonly believed in the United States that school is where people go to get an education. Nevertheless, it has been said that today children interrupt their education to go to school. The distinction between schooling and education implied by this remark  is important.

 Education is much more open-ended and all-inclusive than schooling. Education knows no bounds. It can take place anywhere, whether in the shower or on the job, whether in a kitchen or on a tractor. It includes both the formal learning that takes place in schools and the whole universe of informal learning. The agents of education can range from a revered grandparent to the people debating politics on the radio, from a  child to a distinguished scientist. Whereas schooling has a certain predictability, education quite often produces surprises. A chance conversation with a stranger may lead a person to discover how little is known of other religions. People are engaged in education from infancy on. Education, then, is a very broad, inclusive term. It is a lifelong process, a process that starts long before the start of school, and one that  should be an integral part of one's entire life.

Schooling, on the other hand, is a specific, formalized process, whose general pattern varies little from one setting to the next. Throughout a country, children arrive at school at approximately the same time, take assigned seats, are taught by an adult, use similar textbooks, do homework, take exams, and so on. The slices of reality that  are to be learned, whether they are the alphabet or an understanding of the workings of government, have usually been limited by the boundaries of the subject being taught.

For example, high school students know that they are not likely to find out in their classes the truth about political problems in their communities or what the newest filmmakers are experimenting with. There are definite conditions surrounding the  formalized process of schooling.

The hippopotamus is the third largest land animal, smaller only than the elephant and the rhinoceros. Its name comes from two Greek words which mean "river horse." The long name of this animal is often shortened to the easier to handle term "hippo."

The hippo has a natural affinity for the water. It does not float on top of the water; instead, it can easily walk along the bottom of a body of water. The hippo commonly remains underwater for three to five minutes and has been known to stay under for up to half an hour before coming up for air.

In spite of its name, the hippo has relatively little in common with the horse and instead has a number of interesting similarities in common with the whale. When a hippo comes up after a stay at the bottom of a lake or river, it releases air through a blowhole, just like a whale. In addition, the hippo resembles the whale in that they both have thick layers of blubber for protection and they are almost completely hairless.