Birds
Hawks, eagles and owls all can and will take bobcat kittens or juveniles. Mothers stay with their kittens until their offspring can fend for themselves. However, there are times when an opportunistic hawk could catch a bobcat kitten. Birds of prey are not a significant danger to bobcats but are a possible threat.
Mammals
Other carnivores including coyotes, fishers, cougars, wolves and lynx, are dangerous to bobcats, especially their kittens. They also compete with bobcats, and when food is scarce, the bobcats may go without. Juvenile mortality is directly linked to the food supply, and in times of food shortage many bobcat kittens die. Porcupines are a prey animal but can cause damage to the bobcats with poisonous spines.
Humans
The mammals most dangerous to bobcats are of course humans. Trappers and hunters target bobcats for their fur. In fact as of 2011, bobcat and lynx skins accounted for at least half of all cat fur traded worldwide. In some parts of the United States, humans have eliminated bobcats altogether; both deliberately through trapping for fur or deliberate persecution and accidentally through habitat destruction.
Microorganisms
The real natural enemies of bobcats are not other predators but much smaller microorganisms. Like most other animals, bobcats are vulnerable to a range of infections and diseases including rabies and feline distemper. After humans, the main threats to adult bobcats appear to be diseases and parasites.