Michael McDonald (born February 12, 1952) is an American singer, songwriter, keyboardist and record producer. McDonald's music career spans more than 45 years. His early career included singing with Steely Dan. He joined the Doobie Brothers in 1976 and remained an integral member until 1982, after which he released the first of nine solo albums.

McDonald was recruited by the rock band the Doobie Brothers in April 1975, initially as a temporary replacement for their lead vocalist Tom Johnston after he had become ill during a national tour, but his work with the band proved so successful that they decided to retain him as a full-time member.  As a member of the Doobie Brothers, McDonald sang the lead vocals on some of the band's best-known songs such as "Real Love", "Takin' It to the Streets", "Little Darling (I Need You)", "It Keeps You Runnin'", "Minute by Minute", and "What a Fool Believes" (which became a No. 1 single in the U.S. and earned him a 1980 Grammy Award for Song of the Year along with co-writer Kenny Loggins). At the same time, McDonald appeared as a session vocalist and keyboardist for various artists, including Christopher Cross, Stephen Bishop, Jack Jones, Bonnie Raitt, the rock band Toto and Kenny Loggins. McDonald co-wrote "You Belong to Me" with Carly Simon, which appeared on the album Livin' on the Fault Line.  McDonald reunited as a guest performer with the Doobie Brothers several times since the band's initial dissolution in 1982. He re-teamed with the Doobie Brothers for the track "Don't Say Goodbye" on the band's thirteenth studio album, World Gone Crazy. In March 2014, he reunited with the Doobie Brothers to record a brand-new album featuring the greatest hits of the Doobies' 40-plus-year career. This project was completed in conjunction with Sony Music Nashville. On the album, McDonald shares lead vocals with Sara Evans for "What a Fool Believes", Love and Theft for "Takin' it to the Streets", and Amanda Sudano-Ramirez for "You Belong to Me". The album, titled Southbound, was released on November 4, 2014, as the Doobie Brothers' fourteenth studio album.  On November 5, 2014, McDonald and the Doobie Brothers were featured musical guests on the 47th annual CMA Awards to celebrate the release of Southbound. They were joined by Hunter Hayes, Jennifer Nettles and Hillary Scott in their performance of "Listen to the Music." At the end of the awards ceremony, they were also joined by host Brad Paisley for "Takin' It to the Streets".

Using a quote from the above article, answer the following question: What did he sing for the Doobie Bros?
lead vocals on some of the band's best-known songs such as "Real Love", "Takin' It to the Streets", "Little Darling (I Need You)", "It Keeps You Runnin'", "