fluctuation in rainfall from year to year. Sometimes more than a year 
may elapse with no rain at all. In other times more than the annual 
average may fall in one month. Under such conditions the general aspect 
is much drier than the average annual rainfall would suggest. And the 
luxuriance may vary so much that descriptions written several years 
apart scarcely sound as though the same island were described. On islands 
with large populations of seabirds the injurious effects of TWWgg high 
concentrations of guano seem to be greatly accentuated by these severe 
dry periods. Trees may be severely damaged or killed, as was the case 
with the Kbu trees on Howland (Fosberg,1953). 
In commenting on this variability of rainfall in the South Pacific 
Seelye (1950) wrote that the annual rainfall is most variable along the 
western tongue of the equatorial dry zone, or Howland area, where the 
north-south rainfall gradient is steep. Thus comparatively small dis¬ 
turbances of the controlling atmospheric circulation from normal would 
be expected to produce spectacular changes there. Spectacular changes are 
indeed what we get from the few reports that are available on Howland’s 
yearly rainfall. Ramsay (1927) of the Whippoorwill Expedition doubts 
that Howland has a mean annual precipitation of over 3 inches while 
Doran (1959) states that Howland’s annual precipitation may be estimated 
at 25 inches. Knoch (1927) apparently had the right idea when he reported 
\ 
that the annual precipitation may vary as much as 2k inches from year 
to year. Much more data would be necessary before any definite average 
could be given^for with such anomalies it is understandable that even the 
ten year averages would differ greatly from each other. In particular 
the 1910-1919 average Is pushed up by the two extraordinarily rainy 
