scientist studied the population of a certain species of birds based on their tail length. Initially, most of the birds had medium-length tails, but tail lengths ranged within the species from short to long. Two years later, the study was performed again on the same species of birds. An illustration of the birds with different tail lengths and graphs of the data are shown below. Based on the above data, what inference can most likely be made about this species of birds over the 2 year period between studies?