A statistical population is a set of entities which engages our interest as a set. For example, if we were interested in generalizations about crows, then we would describe the set of crows that is of interest. Notice that if we choose a population like all crows, we will be limited to observing crows that exist now or will exist in the future. Probably, geography will also constitute a limitation in that our resources for studying crows are also limited.
"Population" is also used to refer to a set of measurements or values. Suppose, for example, we are interested in the set of all adult crows now alive in the county of Kent, and we want to know the mean weight of these birds. For each bird in the population of crows there is a weight, and the set of these weights is called the "population of weights".
Statistics > Statistical Population
We use the term statistical population to refer to any collection of units (see statistical model), whether they are concrete objects or a complex conjection of circumstances, that has collective attributes. We presume that we want to use empirical research to learn more about the population.