Clint Barton has always been a sucker for strays. The underdog, the wayward soul. Whatever.

1.

His first clear memory of his instinct to protect a little lost thing was when he was five and found a stray dog on the way home from school. The poor, struggling puppy had clearly been the runt of the litter and had been abandoned on the edge of a desolate alleyway. A small ball of matted white hair and shiny black nose was stashed under his blue school jumper as he sneaked into his house. His mum was working double shifts at the local diner and his dead-beat dad, as per usual, was lying passed out on the couch. He distinctly remembered Barney had gone over to a friend's house, only because when his older brother and saviour returned he had iced Clint's swollen eye and put Band-Aids on the cuts that covered his skinny five-year-old arms and torso. His dad had stumbled around and wondered into his room to find him cradling the canine and had instantly blown up in his face. Little Clint Barton cried and bled over the disfigured body of the dog his father had left in his destructive wake. It only made him more determined to save and help the lost things.

2.

His carnival days were long and wearisome as his brother and himself scrounged for food from skips or bins or whatever they could find, going hungry more nights than not. Still he gave up half of his food for a fortnight when he came across a half-starved fox timidly searching for its next meal just as he was. That encounter was also short-lived when Barney found out and threw rocks at his fox before turning on Clint as well.

3.

The time he spent as a long-distance sniper in the army is something he tries to permanently block from his memory; he still wakes up in cold sweat and gasping for air, a remnant from his military days. The only gift he ever received besides his honourable discharge. On the field and covered in sand and dirt and sweat, his eyes scanning his surroundings when he saw a shadowy small figure running for a nearby bolt hole. Raising his weapon and finger ready at a moment's notice as adrenaline pumped heavily through his veins. He wielded when a dark-skinned gangly kid stared back with dark haunted eyes through his scope. That was the third stray Clint rescued, returning the little boy to his family. They threw him out, 'discharged him' and he was transferred out of the hellish desert by the end of the week.

4.

He had only been at SHIELD for a year when he rescued a nest of birds that were trapped in an air vent on the heli-carrier. Coulson had stormed into his quarters on the ship to find him hand-feeding the chicks that could only have been a few days old. Clint had given him a sheepish smile and shrugged offhandedly, as if it was an average thing for an ultra-intimidating assassin with a ledger and a rap-sheet as long as Barton's to go around saving baby birds. His handler had just pinched the bridge of his nose and instantly back-tracked out of the reformed archer's barracks muttering something about it being 'way too early to deal with your shit Barton' and 'I need a whole load of caffeine to process this.' Clint was one of Phil's most trusted friends, hell he had literally saved the kid's life after he became a gun for hire and got on SHIELD's radar in more than one bad way but even he had to admit that Barton had a weird moral compass… and apparently that meant saving baby birds.

5.

The fifth stray he saved from a life of hell was Natasha Romanoff. He can admit now (back then his ego wouldn't allow it) that the only reason he caught up to her was because she was being hunted from both sides of the track, both SHIELD and the Red Room and every organisation she ever managed to piss off, baying for her blood. Her original Russian captors were after their seemingly perfect killing machine, they wanted their asset back. She had been a mess of tight flesh over prominent bones and after a long, hard fight she was covered in fresh bruises, lacerations and sweat, red hair tangled and hanging in her face as she panted heavily and waited for the final blow. Green eyes met grey almost lazily as she cocked her head to one side and that was when he saw it. That half-dead expression that he had seen on all of the strays he had ever encountered, a kind of brutal acceptance that they weren't going to make it out of that particular rumble alive. He lowered his arrow and extended his arm.

He was the one that kept an eye on her, made sure she ate and got back into condition after three weeks of intense interrogation which was actually harder than it sounded. No one could make the Black Widow do something she didn't want to. Clint Barton was nothing but patient though and he waited, gained her trust enough for her to let him in. He would make sure to his dying breath that no one would take her away.

+1

It was during the clean-up after the Battle of Manhattan that Natasha found a kitten. The feline was cowering under the rubble, hissing with hackles raised along it's spine and a kind of terror that only a cornered animal knows how.

Well she definitely knew that feeling.

"Hey buddy," she crooned softly, letting the emaciated tabby cautiously sniff her extended hands. Deeming her safe he took a tentative step forward and rubbed against her ankles, purring like a motorbike. Carefully picking up the animal she turned to Clint who was nearby and clearing the streets, her face a picture of delight elation, "Hey Clint, can we keep him?"