What hybrid animals are fertile?

 There is a very interesting phenomenon called hybrid speciation by which hybridation between two different species leads to a third one. Needless to say that this process occur because the (sufficient number of) hybrids are fertile.
 Although this type of speciation is more common in plants than in animals, there are some animals species that can be listed in this category (as DNA tests have shown):

• Lonycera fly (Lonicera fly), most likely to be the hybrid of blueberry maggot and snowberry maggot. They feed on honeysuckles, that are also a type of berry, not very innovative in this sense.
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• Great skua or perhaps Pomarine skua (Great skua) : DNA tests have found a great similarity with the genetics of the pomarine skua, despite they look very different. Many  ornithologists now believe either that the Great Skua originated as a  hybrid between the pomarine skua and one of the southern-hemisphere  species , or that the  pomarine skua evolved from hybridization of the great skua and one of  the small Arctic species. In this case it is still on controversy which species came first.

Great skua

Pomarine skua.
(I had curiosity about how dissimilar they are).

• Clymene dolphin, formerly known as the short snouted spinner dolphin (Clymene dolphin): Anatomical and behavioral traits suggested that this species is a hybrid of the spinner dolphin (Stenella longirostris) and the striped dolphin (Stenella coeruleoalba), and DNA testing has shown that it is indeed a hybrid species.