. Brigham Young University science bulletin. Biology -- Periodicals. Biological Series, Vol. 10, No. 4. Ecology of Raptorial Birds 29 TABLE 9 Number (and percentage) of Ferruginous Hawk nests in various sites 1967 1968 All nests' Nest sites Unoccupied Occupied Unoccupied Occupied Unoccupied Occupied Ground Juniper Cliff Cliffrose Totals 18 11 1 1 31 (58) 8 (35) 4 (3) 1 (3) 0 (100) 13 (62) (31) (7) (0) (100) 24 9 2 0 35 (69) 6 (26) 7 (5) 0 (0) 1 (100) 14 (43) (50) (0) (7) (100) 42 20 3 1 66 (64) (30) (5) (1) (100) 14 (52) 11 (40) 1 (4) 1 (4) 27 (100) "This information was recorded for all
. Brigham Young University science bulletin. Biology -- Periodicals. Biological Series, Vol. 10, No. 4. Ecology of Raptorial Birds 29 TABLE 9 Number (and percentage) of Ferruginous Hawk nests in various sites 1967 1968 All nests' Nest sites Unoccupied Occupied Unoccupied Occupied Unoccupied Occupied Ground Juniper Cliff Cliffrose Totals 18 11 1 1 31 (58) 8 (35) 4 (3) 1 (3) 0 (100) 13 (62) (31) (7) (0) (100) 24 9 2 0 35 (69) 6 (26) 7 (5) 0 (0) 1 (100) 14 (43) (50) (0) (7) (100) 42 20 3 1 66 (64) (30) (5) (1) (100) 14 (52) 11 (40) 1 (4) 1 (4) 27 (100) "This information was recorded for all nests, regardless of the years of construction, occupation, or abandonment in 1967 were miles and miles, respec- tively. In 1968 the maximum distance was miles, and the minimum distance of mile separated two nests on the same long hill, one facing south and the other north (Fig. 9, Nests 4b and 7b). Supernumerary (alternate) nests were found for 25 nesting pairs, or 93 percent of 27 occu- pied nests visited during 1967 and 1968. The hawks often constructed entirely new nests each year. In 1967, 58 percent of the occupied nests had been entirely constructed during the spring of that year. In 1968 43 percent of the occupied nests were new, even though older nests were repaired and attended regulary until eggs were laid. Pairs with more than one nest had an average of supernumerary nests. One pair attended five nests, no two of them farther apart than mile; 4 pairs had one super- numerary nest each; the remaining 22 pairs had two or three additional nests. Nest Sites, Composition, and Size Of the 27 occupied nests found, 52 percent were located on the ground (Table 9). As a general rule, these nests were easily accessible from nearly every direction. The next most common nest site (11 active nests )was the Utah juniper, a tree characterized by large limbs that provide ideal support for the heavy, bulky nests. Juniper nests were usually located from six to t
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