Statement 1 - The size of a population for any species is  a static parameter.

Statement 2 -  If a new habitat is just being colonised, immigration may contribute more significantly to population growth than birth rates.

Statement 2 is correct and 1 is incorrect.

The size of a population for any species is not a static parameter. It keeps changing with time, depending on various factors including food availability, predation pressure and adverse weather. In fact, it is these changes in population density that give us some idea of what is happening to the population – whether it is flourishing or declining.

Under normal conditions, births and deaths are the most important factors influencing population density, the other two factors assuming importance only under special conditions. For instance, if a new habitat is just being colonised, immigration may contribute more significantly to population growth than birth rates.