1977 Walter D. Koenig 17 Melanerpes formicivorus 4 Hastings Reservation 17 June 9:50. Now that it had cleared up outside I ventured to open the nest and measure the 4 babies, all of whom have hatched. They were all marked with MagicMarker dots and returned within 1/2 hour. See Nest Record (pp. 9-10) for measurements. ♂261 was the bird flushed out of the hole. Finally, however, I can state with some certainty that the incubation period for the California Woodpecker is indeed several days shorter than previously thought. For this nest, the maximum time between the laying of the last egg to its hatching was 12 days, 0 hours; minimum 11 days, 0 hours (plus an unknown number of hours which I can perhaps estimate for how long they probably took to hatch from the stage of pipping I found them in yesterday evening). 18 June 1420. Watching: ♂ in hole. 1452. ♀16 entered the hole. [♂ apparently left it]. 1509. ♂ [illegible] " " . ♀ left 1511. ♂322 " " " (1511.5. ♂ [illegible] back almost immediately; entered hole. 1514. ♂ [illegible] at hole!! I fear ♂364 may have lost his wing-streamer and be messing things up entirely. I'd best quit and watch with the spotting scope carefully from now on. 19 June 1000. Measured the 4 keets. 21 June 1000. " " " . No sign of feather tracts yet. Noone in hole when I came over to open the hole. 1620. Watching. [illegible] ♀16 in hole. (Using spotting scope this 1625. ♂261 (for sure) took over