Valtteri Bottas led team mate and Formula One championship leader Lewis Hamilton in a Mercedes one-two in first practice for the Spanish Grand Prix on Friday.
The Finn, who dropped to third overall in the standings after last Sunday's 70th Anniversary Grand Prix at Silverstone, clocked a best time of one minute 16.785 seconds on a hot morning at the Circuit de Catalunya.
The Finn also reported hitting a flying bird during the session.
Six times world champion Hamilton was 0.039 slower with Red Bull's Max Verstappen - now second overall after winning at Silverstone to end Mercedes' opening run of success - third fastest but 0.939 off the Finn's pace.
Hamilton, who has a 30 point lead over Verstappen, has won the last three Spanish Grands Prix and is going for his fourth win in six races this season on Sunday.
Ferrari's Charles Leclerc was fourth fastest, 1.185 slower than Bottas, with German team mate Sebastian Vettel fifth and only 0.011 off the Monegasque's pace.
Vettel has a new chassis for the race after Ferrari found a crack in the one he had used last weekend.
Haas's Romain Grosjean, whose car also has a Ferrari engine, was a surprise sixth quickest ahead of Racing Point's returning Mexican Sergio Perez, who missed two races after testing positive for Covid-19.
Perez was using the slower medium tyres rather than the quicker softs used by those ahead of him.
Briton George Russell sat out the session, handing his car to Israeli development driver Roy Nissany, who was the slowest driver on track.
Nissany lapped 3.879 seconds slower than Bottas but only 0.3 adrift of Williams' Canadian driver Nicholas Latifi.
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