Abird count was done on the island and the small tree finch was found in all regions. state one possible
reason why the small tree finch is able to inhabit the entire island.

One very possible reason is because it is the last remaining species of finch that has been most adapted to this specific environemnt. Because it was most adapted to this environment, it has also been the only finch to survive until to the day when the counting was done. 

4, two dominant and two recessive