Walking Through Treacle

The invisibility charm could be useful. Fawkes couldn't very well go into the Owlery - unlike Zeus, he emphatically wasn't a post-bird -without a bit of help from an invisibility charm, or very good reason.

Sometimes it had been to talk to Lady Hedwig. She was a very beautiful lady, and some of the others said she had designs on him. She and he both said it was rubbish, it was merely a matter of prudent familiar liaison. Her human had needed him more than once.
Generally they met on the Astronomy tower - she liked to have the latest gossip for the other owls, and no bird in their right mind would voluntarily go to the tower, busy as it was with humans. He liked to go there - well he maintained it was a good place to practice his singing. If they had less than honourable intentions, then the young humans would run.

Zeus' human had come up there often, but never with a female. Usually he hid, something Fawkes didn't understand. After all, a well trained bird never looked in on a couple of amorous humans, and equally hoped that the humans would forgive their own indiscretions. If they ever found out.

Unfortunately Albus always did. Bloody omniscient owners - he knew what Fawkes was thinking before Fawkes even thought it. And, as if that wasn't enough, he'd tell Severus. Oh, he liked the boy well enough, always needing to be rescued at least 3 times a week in high season. Usually from the Elder Blond's mansion. That was how he'd met Zeus the first time.

Albus never says anything. He just teased him about his taste in black strangers, suggesting he should find another phoenix, settle down, have a nestling. More than once Fawkes wondered if he should engineer a delivery to Severus, just so he could fly wing tip to wing tip with that gorgeous creature.
The problem was that everyone knew Phoenixes were never mere post birds and he couldn't just pop up like that. Oh, he'd love to brush feathers with Zeus, but it had to be realistic. He was not going to act like a silly hatchling. He was going to play it cool, perhaps preen himself casually. And he was not going to make a fool of himself over Lucius’ Malfoy’s owl.

Lady Hedwig came over, and they talked for a while. He thinks she’s got him down as the gay best friend that every female post-owl wants. It’s too confusing. It’s hard enough to tell male and female apart as it is.

He’s sitting on a turret now, not far from home. Zeus is leaving the building, apparently on an errand, and Fawkes takes to the wing, wishing, just for once, they could dance, beak to beak, or walk easily on solid ground. Wheeling round he curses his short turning circle, and glides over the flight path of the black owl. Somewhere below him, a dark cry prevents his song.