Seasonal declines in rates of renesting following clutch loss are common fe
atures of avian brooding, and are generally thought to reflect underlying s
easonal declines in food availability that lower survival prospects for lat
e-season offspring. However, in Thick-billed Murres (Uria lomvia), long-liv
ed Arctic seabirds that lays a single-egg clutch, previous research has sho
wn that early laying females will continue to relay until late in the layin
g period. Moreover, hatching success is similar between first and replaceme
nt attempts, as are nestling growth and survival, when parental quality is
controlled. I compared survival between departure from the breeding site an
d recruitment age (4-5 years) for Thick-billed Murres that hatched from fir
st and replacement eggs, but that were raised by parents that laid their fi
rst eggs early in the season. Replacement-egg offspring hatched and departe
d the colony about three weeks later than did first-egg offspring,but despi
te that, they were no less likely to survive to recruitment age. That resul
t indicates that the potential fitness payoff from a replacement egg is sim
ilar to that from a first egg for the more capable members of the populatio
n. I suggest that an adequate and predictable late-season food supply ultim
ately underlies the considerable relaying capacity exhibited by Thick-bille
d Murres.