Cockatwice

The cockatwice is physically similar to its ancestor, which it replaces. It has only minor changes of proportion, crest shape, and ear position. Its biggest difference is in behavior: its typical body posture resembles a playful dog. It is not actually playful, however. The posture allows it to direct echolocation frontwards, letting it "see" where it is going, and its frontwards-directed ears are better able to hear the reflected sound waves. The mouth is often open not for directing sound pulses (as in bats) but for ease in depositing "breadcrumbs": small, crumbly pellets deposited at regular intervals at otherwise "low-visibility" hazards, such as the silk lines of breeding male tyrant gossalizards. The porousness of the objects stands out in their echolocation, making it much easier to detect silk lines that are otherwise too thin to be "visible." This allows them to avoid the territories of breeding males. Unfortunately for them, only breeding males use silk lines as territorial markers, so this defense is useless against females or immature males. While cockatwices' ancestors were active at night, and thus could avoid tyrant gossalizards that hunted typically at dusk or dawn, over time tyrant gossalizards have slightly changed their hunting times, increasing their probability of finding twilight ridgehorns about.* This was a worthwhile development because twilight ridgehorns were ideal prey: they were easily overpowered on account of their smaller size and tended to stumble into tyrant gossalizard territories. Consequently, twilight ridgehorns adapted, creating a system of "breadcrumbs" to decrease likelihood of stumbling into high-risk areas.

Author's Notes
Notes: *Similarly to the Anopheles mosquito. If each Generation is about two million years, and the tyrant gossalizard originated in Generation 152, then tyrant gossalizards have had about 10 million years to develop this behavioral change. That's plenty of time for something so minor as slightly later/earlier hunting times.