My sister, Sadie, has become the sentinel Scottie of our clan. If someone rings our doorbell, she is at the door, jumping up and down, barking furiously. Even when she hears a doorbell on TV, she barks and lets everybody know.
When we Scotties are cruising the backyard and Sadie hears a bird chirping, she will bark a response and heaven forbid, if she hears another dog barking in the neighborhood, she has to chime in. Sadie also likes to bark when she hears a car door slam or if she hears human voices outside. She definitely likes to make her presence known!
Wen is not thrilled when the sentinel barks outside and Sadie has gotten in trouble for her loud high shrill barking on many occasions. It has not phased her in the least though and the sentinel Scottie continues to do her job. In my opinion, she is just a nosy chatty girl!

Sentinel Sadie