Given an array of bird sightings where every element represents a bird type id, determine the id of the most frequently sighted type. If more than 1 type has been spotted that maximum amount, return the smallest of their ids.

migratory-birds.py

def migratory_birds(arr):
    index = dict()
    max_sight_count, min_ids = 0, 6
    
    for bird_id in arr:
        if bird_id not in index:
            index[bird_id] = 0        
        index[bird_id] += 1
        max_sight_count = max(index[bird_id], max_sight_count)
             
    for bid, sight_count in index.items():
        if sight_count == max_sight_count:
            min_ids = min(min_ids, bid)
            
    return min_ids

print(migratory_birds([1,2,1,5,4,4,4,5]))