i74 



Hcmciii — Our Living Resources 



272 species 



All Species 



Of the 272 species resident now or recorded 

 as visitors (Pyle 1992). roughly 40<7f are perma- 

 nent residents, about equally divided between 

 native and alien species (Fig. 4). The breeding 

 visitors, all seabirds. are relatively few. The 

 remaining 55% of the species are nonbreeding 

 visitors. This large percentage for nonbreeding 

 visitor species is not surprising, since these 

 include many species that have wandered to 

 Hawaii as individual stragglers. But in terms of 

 total individuals, the picture is reversed. The 

 nonbreeding visitor species account tor proba- 

 bly the fewest individuals, while the breeding 

 visitor seabirds have much larger populations in 

 their huge nesting colonies in the unpopulated 

 Nonhwest Hawaiian Islands. But the largest of 

 all in total population are the alien residents, 

 which include the ubiquitous Japanese white- 

 eye (Zostewps japoiiiciis). zebra dove 

 (Geopelia striata), and other residents found 

 almost everywhere in the main populated 

 islands. 



Birds known to have been in Hawaii in the 

 past, but which are no longer there, can be sum- 

 marized as follows: 16 species (resident-native) 

 have become extinct since Captain Cook's visit: 

 35 or more species (subfossils, probably native 

 residents) were extinct before Captain Cook's 

 visit: and about 150 species are alien introduc- 

 tions not established. Adding these to the 272 

 species here now constitutes about 475 species 

 of birds known to have occurred in Hawaii. 



Trends 



l^:Sl Resident species - native 



Hi Resident species - alien 



^1 Visitor species - breeding 



^H Visitor species • nonbreeding 



Fig. 4. Bird species currently resi- 

 dent in or visiting Hawaii. 



Native Landbirds 



Meaningful estimates of total populations of 

 landbirds in Hawaii are difficult to derive. 

 Native species have been confined, at least since 

 Captain Cook's visit, to thickly vegetated and 

 wet higher elevation forests on sleep slopes or 

 occupied by deep muddy bogs. Not surprising- 

 ly, naturalists over the years could make no real 

 estimates of landbird populations for the island 

 group or even for an individual island, despite 

 the relatively small total areas that were occu- 

 pied by many of these endemic species. 



It was not until the Hawaii Forest Bird 

 Survey in the late 1970"s to early 1980"s that 

 thoroughly planned fieldwork was conducted, 

 leading to the first comprehensive population 

 estimates for native Hawaiian landbirds. 

 Pioneering techniques for field surveys in such 

 terrain and for statistical analysis were used to 

 obtain population estimates for the native land- 

 bird species on all forested islands except O'ahu 

 and Ni'ihau (Scott et al. 1986. 1988). For O'ahu 



Island, Shallenberger's surveys during the latter 

 1970's in the Koolau Mountains (Shallenberger 

 and Vaughn 1978) and in the Waianae 

 Mountains (unpublished) have been the most 

 comprehensive. 



More recently, Ellis et al. ( 1993) estimated 

 populations for each native forestbird on each 

 Hawaiian island, based on information available 

 at the end of 1992. These are not directly com- 

 parable with the earlier estimates derived from 

 field surveys. However, these estimates and 

 numerous other less comprehensive surveys 

 over the years involving some species on some 

 islands do reinforce a general consensus that 

 Hawaiian forestbirds have declined steadily 

 both in the long term during the past century 

 and in the short temi in the past decade. 



Resident Waterbirds and Visitors 



The Hawaii Division of Forestry and 

 Wildlife has conducted statewide counts of wet- 

 land birds semiannually during recent decades. 

 These have included resident wetland species 

 (not the seabirds) and nonbreeding visitor 

 species. Variations in these population counts 

 over the years rellect changes in available wet- 

 land habitat, thoroughness of coverage, and 

 possibly some irregular interisland movements. 

 Engilis and Pratt (1993) analyzed these 

 statewide counts for the resident species during 

 1978-87. Data from earlier surveys covering 

 only certain islands and using less rigorous 

 counting techniques are not readily comparable. 

 Longer-term historical trends in populations of 

 four endangered wetland species are being 

 examined for the Hawaii Wetland Bird 

 Recovery Plan now in preparation by the 

 Recovery Team for the U.S. Fish and Wildlife 

 Service (A. Engilis. personal communication). 



The breeding visitor seabirds gather to nest 

 in large colonies in the Northwest Hawaiian 

 Islands. Gross estimates of population numbers 

 for these species made in the 1960's and again 

 in the late 1970's are not comparable for trends 

 analysis because of varying techniques used in 

 attempting to arrive at meaningful numbers in 

 these huge colonies totaling in the millions. 

 Harrison" (1990) discussed the difficulties 

 involved in making representative counts and 

 finds no evidence of long-term trends in species 

 numbers, although some wide fluctuations 

 occurred earlier this century. One notable fea- 

 ture has been the return of the Laysan albatross 

 (Diomedea immutabilis) as a breeding visitor to 

 Kaua'i and O'ahu in the main Hawaiian Islands. 

 Since 1977. a steady increase in numbers now 

 measured in the hundreds has local interest but 

 has had a rather small effect on the total 

 statewide population of millions. 



