"He sure does have feathers"
Red named him that because he has feathers.
Feathers was a solitary Pidgey quite young. He had recently fledged the nest and was comfortable hunting for his own food in solitude. Sometimes he would approach trainers because humans would sometimes give him free food. Pidgey are rather docile in nature, and this one was no exception.
Since Pidgey are usually docile, they are popular to catch among young trainers because it is easy to do even with weak pokemon. However, very few trainers stick with their Pidgey in the long run. Trainers will often release them once they've gotten enough use.
Red, however, had read about powerful Pidgeot before. He knew that while most trainers weren't capable of raising a Pidgey to those levels, he had the confidence that he could.
So, he went into the Wilderness and started bird watching. He would keep his eyes open for Pidgey that seemed promising, if he could tell they knew specific moves, or seemed particularly strong or promising. He saw feathers hunting for food, thought he seemed promising, then battled and caught him with the help of Leaf the Bulbasaur.
Feathers definitely didn't mind being caught by a trainer, because that meant it got free food now! He also got along with Leaf quite well, since Leaf could provide him with seeds to eat.
Red was very confident in Feathers abilities to become strong and powerful, so Feathers would believe in himself as well. Especially when it came to battling Blues Pidgey, it became a matter of pride for both Red and Feathers to win these battles.
Red instilled in the Pokemon a determination to win, and a desire to be powerful. It was a lot of hard work for both of them, but feathers was a mainstay in the team the entire time.
When feathers evolved into a pidgeotto, there was a clear sign it was different. Most Pidgeotto have pale red feathers extending off the top of their head, but this Pidgeotto's was bright red, then gradiated into an orange and yellow. A Pokemon evolving to match their trainer more was a clear sign of a strong bond.
The Pidgeotto took a bit longer than normal to evolve into a Pidgeot, as red and feathers were more focused on perfecting their skills than they were learning new ones. They would only start learning new skills once they had perfected the last.
When the Pidgeotto finally evolved into Pidgeot, he was larger than most Pidgeot. He had a longer wingspan as well.
He is a very serious bird. He's very proud of his power, and believes in hard work. He holds an affection for his teammates, but is a bit more serious than most of them and will sometimes get tunnel vision when it comes to pursuing a goal. But, when the sun sets, he will be the first to open his wings so that his friends can cuddle under his warm feathers.
While on the mountain, many of his feathers turned paler or white. This would help him camouflage more in the surroundings on the snow covered mountain.
Alongside Sunny the Arcanine, feathers was in charge of keeping the team warm. Being a large bird, he could hide the pokemon in his downy feathers to keep them warm underneath him.
feathers has supernaturally good eyesight. Often, he would fly up into the air to survey surroundings. If the Pokemon were spread out, he could fly up and keep an eye on all of them. He would often fly ahead to check for safe spaces for them to rest at, and also to check if there were any dangerous territorial pokemon up ahead.
He would not say that he enjoyed the mountain, but he was not one to question his trainer either.
Feather is free range. Red and blue in their Pokemon gym usually keep their Pokemon out of their pokeballs for them to roam around, and for feathers, that means being able to fly long distances. Often this can be miles away from the gym, but it's never too far away that if red calls for him he wouldn't notice.