  We study the 36 brightest radio sources in the Subaru/XMM-Newton Deep Field
SXDF). Using MIPS 24 micron data from Spitzer we expect to trace accretion
activity, even if it is hidden at optical wavelengths, unless the obscuring
column is extreme. Our results suggest that in the decade or so below the break
in the radio luminosity function that at least half, and potentially nearly
all, radio sources are associated with accreting quasar-like objects. This is
not true at lower radio luminosities where the quasar-like fraction approaches
zero once compact sources are excluded.
