The White-tailed Kite -
A Success Story?

by Betty Burridge

A VERY INTERESTING RECENT record of a pair of White-tailed Kitesraising a second clutch of young in one season brings forth memories andquestions about the viability of this once very threatened raptor.

On September 4, 1996, on Sonoma Mountain an adult White-tailed Kitewas observed sitting on a nest. Thoughts of the length of daylight (similarto that of spring) triggering hormonally related breeding activities wereentertained, until a downy head popped up. Then a second head moved. Thiswas the real thing.

By September 26th three large youngsters in immature plumage were standingand stretching. (A Cooper's Hawk swooping out of nowhere along thetree line was vigorously diverted away from the babies by a parent, whothereafter occupied a more obvious perch.)

This and other kite breeding records (one just adjacent to the Luther BurbankCenter south fence, and one on Bicentennial Drive near the intersectionof Mendocino Avenue) indicate a healthy 1996 breeding population. However,the Bicentennial Drive site has already been destroyed by drastic earthmoving work to stabilize the hillside in preparation for retail (Yardbirds)construction along Mendocino Avenue. And the Luther Burbank site may soonbe developed as well.

So where can these birds and their off-spring go to breed? They can't justpick the next tree in sight. Assuming by their success at fledging youngthat they already 'owned' the safest, richest, most secluded, i.e. bestterritory for nesting in the immediate area, only second-rate nearby siteswould be available. So the kites may be forced to travel some distance tothe next ideal nesting locations. However, these most likely will be alreadyoccupied by other kites. In addition, the survivors of the broods from thisyear will also be competitors for nesting territories. In this time of increasingdevelopment, and concomitant loss of open space and thus, White-tailedKite habitat, it seems worth reviewing the precarious population historyof the White-tailed Kite in this century.

This kite was considered common in (central) valley and lower foothill territoryprior to 1895 by Grinnell and Miller in Birds of California (1940),and common in parts of the San Francisco Bay Area in the late 1890's byGrinnell and Wythe in Directory to the Bird Life of the S. F. Bay Region(1927). But that abundance was short lived.

Ralph Hoffmann, in his Birds of the Pacific States (1927) tells usthat "the softness of its color and the confiding and gentle natureof (this kite), so different from the wildness of most birds of prey, makea strong appeal to lovers of nature but not alas! to the usual run of gunners.There are probably not more than 50 pairs left in California (in 1927),and in spite of protection by law the number is slowly decreasing."

Fortunately, since then the population numbers and the range of this raptorhave increased remarkably, slowly at first with Grinnell and Miller notingin 1940 "a slight trend to recovery" and with the species stillbeing described as rare in the 1965 edition of Birds of North Americaby Robbins et al. This bird is still protected as a species of concern,being recorded in the California Department of fish and Game - Natural DiversityData Base.

Reasons for its decline earlier in the century may have been a combinationof the aforementioned 'gunners' along with an inflexibility or inabilityof the bird to exploit existing or dwindling food and habitat resources.Dave Schuford also suggests in The Marin County Breeding Bird Atlas(1993) that overzealous egg collecting may also have threatened this birdsince its "eggs were highly prized because of their scarcity, becauseof the variability between egg sets, and because (the) eggs are among themost beautiful of those of all North American birds." Now, however,according to Paul Ehrlich et al. in The Birders Handbook (1988) thissame bird seems to have been "probably the only raptor to have benefittedfrom agricultural expansion, aided by high adaptability to habitat disruptionand increased abundance of rodents."

So now we have a dilemma. On the one hand, our local White-tailed Kitesseem to be breeding vigorously, even producing two clutches in a season.(Paul Ehrlich et al. The Birder's Handbook [1988] tell us that thiskite is one of the few raptors that may 'double clutch'.) On the other handtheir preferred habitat of rodent-rich agricultural areas near sources ofwater and oak woodlands are decreasing. Whether this is about to becomehistory repeating itself may just depend on how resilient the White-tailedKite really is in adapting to the changing world, and how fast and howmuch we humans allow those changes to take place.

November 1996, Volume 30, Number 3

The White-tailed Kite -A Success Story?

The White-tailed Kite -
A Success Story?