Answer:
Red allele frequency will be highest in population II
Population III can undergo bottleneck effect 
The frequency of the brown allele will least likely be altered in the population I
Step-by-step explanation:
Population I - 
Total population - 

Brown birds - 

Red birds - 

Population II
Total population - 

Brown birds - 

Red birds - 

Population III
Total population - 

Brown birds - 

Red birds - 

Frequency of red birds in population I 

Frequency of red birds in population II 

Frequency of red birds in population III

Red allele frequency will be highest in population II and it will be equal to 
 as compared to 
 in case of population I and III
Population III can undergo bottleneck effect because of smaller population size 
The frequency of the brown allele will least likely be altered in the population that has highest brown individual , i.e population I