At 01:03:00, the bird flies to the island. When the cat wakes up, there are no dogs inside the boat. Later, the new dogs are in the boat again.
A horn appeared in the Lemur's basket quite some time after it got dragged on board. The first time the horn is visible was when it was getting washed away as they were leaving. After the cat's dream sequence the next shot of the basket shows the horn and also all subsequent shots seem to show it. Finally, when the cat is running towards the amphitheater looking at stuff from the basket that were scattered on the ground, there is the horn.
In reality, secretary birds do not feed by swooping down and grabbing fish (or cats) in their claws the way an eagle or osprey would. These long legged birds are terrestrial predators, who stalk their prey in open savannas and grasslands and seize them in their beaks.