French frigate Cléopâtre (1781)

A plan of the Oiseau taken in 1793

The Royal Navy commissioned Cléopâtre as HMS Oiseau in September 1793 under Captain Robert Murray.[4] On 18 May 1794 he sailed her from Plymouth to Halifax in a squadron commanded by Rear-Admiral George Murray. Between 1793 and 1795, the Russian naval officer Yuri Lisyanski sailed aboard Oiseaux as a volunteer. Between 1803 and 1806 he would captain the Russian-American Company's sloop Neva on the first Russian circumnavigation of the world.

In June 1794 Oiseau and Argonaut seized fourteen French vessels of a convoy of 25, all loaded with flour, naval stores, beef, and pork. The vessels were American-owned and had sailed from Hampton Roads with two sets of papers, one set showing the cargo going to England and the other giving their destination as France. The British sent the vessels into Halifax.[5]

In July, Argonaut, Oiseau, Thetis, and Resolution captured Potowmac and True Republican.[6]

On 8 January 1795, Argonaut captured the French Republican warship Esperance on the North America Station.[7] Esperance was armed with 22 guns (4 and 6-pounders), and had a crew of 130 men. She was under the command of lieutenant de vaisseau de St. Laurent and had been out 56 days from Rochfort, bound for the Chesapeake. Argonaut shared the prize money with Oiseaux.[8] Because she was captured in good order and sailed well, Rear Admiral Murray put a British crew aboard and sent Esperance out on patrol with Lynx on 31 January.[7]

In 1798, Oiseau served in the Indian Ocean, where she captured the French Réunion on 1 September. On 21 April 1799 her boats went into Saint Denis on the Íle de Bourbon and cut out two merchant vessels, Denree, which had a cargo of bale goods and coffee, and Augustine, which had a cargo of rum and arrack. Augustine was lost in St. Augustine's Bay.

On Monday, 26 January 1801, at 8.00 a.m., at 45°N 12°W, Oiseux, under Captain Samuel Hood Linzee fell in with and chased Dédaigneuse, which was bound from Cayenne to Rochefort with despatches. By noon the following day, with Cape Finisterre in sight, Captain Linzee signaled to Sirius and Amethyst, which were in sight, to join the pursuit. Dédaigneuse maintained her lead until 2.00 a.m. on the 28th when came within small arms range. Dédaigneuse opened fire from her stern-chasers, and the two British ships returned fire. After a running fight of 45 minutes, two miles off shore near Cape Bellem, fire primarily from Sirius had cut Dédaigneuse's running rigging and sails ). She had also suffered casualties with several men having been killed, and 17 wounded, including her Captain and fifth Lieutenant. She then struck her colours. Unfavourable winds kept Amethyst, from getting up before Dédaigneuse had struck. Sirius was the only British ship to sustain any damage (rigging, sails, main-yard and bowsprit) in the encounter and there were no fatalities on the English side. Captain Linzee declared the encounter a long and anxious chase of 42 hours and acknowledged a gallant resistance on the part of Dédaigneuse. At the time of the encounter she was armed with twenty-eight 12-pounder guns. Linzee described her as "a perfect new Frigate, Copper fastened and sails well...". He sent her into Plymouth with a prize crew under the command of his first lieutenant, H. Lloyd.[9] The Admiralty took Dédaigneuse into the Royal Navy under the same name HMS Dedaigneuse.

On 28 January, along with HMS Sirius, she captured 3 French frigates off Ferrol.

On 16 September 1800, Oiseau, Wolverine and the cutter Fly captured Neptunus when Neptunus was going into Havre de Grace. The next day Wolverene brought Neptunus into Portsmouth, together with her cargo of naval stores that Wight had captured [10][11]

In February 1801 Captain Lord Augustus Fitzroy assumed command.[4]

In mid-afternoon on 16 March the privateer schooner Lord Nelson, Captain Humphrey Gibson, was between the Isle of Wight and Portland when a lugger came into sight, under chase by a larger vessel. Humphrey immediately changed his direction to attempt to cut the lugger off. After a chase of four hours, Lord Nelson caught up with the lugger, which immediately surrendered. The lugger turned out to be the French privateer Espoir, of 14 guns and 75 men, under the command of M. Alegis Ballet. She was two days out of Saint-Malo and had taken nothing. There were no casualties. As Lord Nelson was taking out the prisoners Oiseau, Captain Augustus Fitzroy, came up.[12][lower-alpha 1]

Captain John Murray replaced Fitzroy in August, and was replaced in turn in December by Captain John Phillips.[4]

In June 1806 Oiseau was commissioned under Lieutenant Walter Kennedy as a prison hulk at Portsmouth. In 1812 Lieutenant William Needham succeeded Kennedy. She was laid up in December, but then lent to the Transport Board.[4]

In 1814 she was under the command of Lieutenant John Bayby Harrison. She was then put in ordinary in 1815.[4]