Other characteristics related to their hunting heritage are a size suited for scrambling in and out of boats and an inordinate love for water. Golden Retrievers are exceptionally trainable—due to their intelligence, athleticism and desire to please their handlers—and excel in obedience trials. At that time, wildfowl hunting was a popular sport for the wealthy Scottish elite, but the existing retriever breeds were inadequate for retrieving downed game from both water and land. Retrieving from both land and water was necessary because the hunting grounds of the time were pocketed with marshy ponds and rivers. Consequently, the best water spaniels were crossed with the existing retrievers, resulting in the establishment of the breed today known as the Golden Retriever. The Golden Retriever was first developed near Glen Affric in Scotland, at 'Guisachan', the highland estate of Dudley Marjoribanks, 1st Baron Tweedmouth. The breed is thought to have originated from the now-extinct Russian tracker dog.