24 



Binh — Oiii Liiiiii; Ri'suunes 



by 



Thomas E. Martin 



National Biological Sen'ice 



David F. DeSante 



The Institute for Bird 



Populations 



Charles R. Paine 



Montana Cooperative Wildlife 



Research Unit 



Therese Donovan 



University of Montana 



Randall Dettmers 



Ohio Cooperative Research 



Unit 



James Manolis 

 Minnesota Cooperative Fish 

 and Wildlife Research Unit 



Kenneth Burton 



The Institute fin- Bird 



Populations 



iMihcalthv populations in terms of productivity 

 or survival probJL-nis (Marlui and Guepel 1993). 

 In addition, demographic data can help deter- 

 mine whether population declines are the result 

 of low breedmg productivity or low survival in 

 migration or winter Breeding productivity data 

 also can help identify habitat conditions associ- 

 ated with successful and failed breeding 

 attempts. Such information is critical for devel- 

 oping habitat- and land-management practices 

 that will maintain healthy bird populations 

 (Martin 1992). Here, we provide examples of 

 the kinds of information that can be obtained by 

 bioad-scale demographic studies. 



Demographic Programs 



The Monitoring Asian Productivity and 

 Survivorship (MAPS) and Breeding Biology 

 Research and Monitoring Database (BBIRD) 

 programs were developed to gather the demo- 

 graphic data needed to provide early and locali- 

 ty-specific warning signals of population prob- 

 lems. MAPS uses large, stationary mistnets to 

 capture and examine young and adult birds for 

 between-year changes and to determine 

 long-term trends in adult population size, pro- 

 ductivity, and adult survival. BBIRD locates 

 and monitors bird nests to study changes in 

 nesting success, determine causes of nesting 

 failure (e.g., weather, habitat, nest predation, or 

 nest parasitism), and identify habitat conditions 

 associated with successful reproduction. 

 Though both programs are new. they are grow- 

 ing rapidly. We present example data to demon- 

 strate initial results and burgeoning potential of 

 these programs for the future. 



MAPS 



Initiated in 1989 and coordinated by The 

 Institute for Bird Populations. MAPS is a coop- 

 erative effort among federal and state agencies. 

 private organizations, and bird banders to oper- 

 ate a standardized continent-wide network of 

 mist-netting and banding stations during the 

 breeding season (DeSante 1992; DeSante et al. 

 1993a. " 1993b). A typical MAPS station 

 involves about ten 12-m (39-ft) mistnets over a 

 20-ha (49-acre) area. All birds captured 

 throughout the breeding season are identified to 

 species, age. and sex. and are banded with U.S. 

 Fish and Wildlife Service bands. 



As of 1992. 170 stations were in operation 

 and more than 94.000 captures of more than 

 200 bird species were recorded. The number of 

 adult birds captured is used as an index of adult 

 population size while the proportion of young 

 provides an index of posttledgling productivity 

 (Baillieetal. 1993). 



BBIRD 



The BBIRD program, initiated in 1992. pro- 

 vides detailed information on nesting productiv- 

 ity and habitat needs of nongame birds at a 

 national scale. BBIRD is a cooperative effort 

 among biologists studying nesting productivity 

 at local sites across the country. Participants fol- 

 low a standard field protocol to obtain raw data 

 on nesting productivity, causes of reproductive 

 failure, vegetation measures at several spatial 

 scales, and point counts (bird counts). Data 

 Uom each local site are overseen by individual 

 independent investigators who can obtain com- 

 parative information from other sites. In addi- 

 tion, overview analyses to identify national and 

 regional trends are conducted at the Montana 

 Cooperative Wildlife Research Unit. 



BBIRD study sites are in large forested 

 blocks to minimize fragmentation effects and 

 prinide baseline information on productivity in 

 undisturbed habitats as well as in auxiliary sites 

 that have no habitat restrictions (e.g.. grazed, 

 fragmented, or logged sites). The BBIRD pro- 

 gram now includes 23 sites in 17 states. Over 

 S.OOO nesis of more than 150 bird species were 

 monitored during the first 2 years of the pro- 

 gram. 



Variation in Productivity 



The data provided by MAPS and BBIRD 

 suggest that weather may be an important influ- 

 ence on population dynamics at large and even 

 continental scales. Prior data from 

 constant-effort mist-netting in scrub habitat on 

 the west coast have suggested that avian pro- 

 ductivity may peak during average weather con- 

 ditions and may he depressed when weather 

 conditions deviate from average (DeSante and 

 Geupel 1987). These facts are especially impor- 

 tant because one of the most important ecologi- 

 cal results of global climate change may be a 

 greater annual variability in both local and 

 large-scale weather conditions. 



Changes in indices of adult population size 

 and postfledging productivity from the first 4 

 years of MAPS are presented for all species 

 pooled and for each target species caught at 10 

 or more stations in 1992 in the Northeast and 

 Northwest regions. These data indicate that pro- 

 ductivity varied greatly from year to year, pre- 

 sumably a result of large-scale weather condi- 

 tions (e.g.. precipitafion and temperature) just 

 before and during the breeding seasons. 

 Productivity was poor across most of North 

 America, but especially in the eastern third of 

 the continent in 1990. Adult population sizes 

 declined significantly in the East in 1991. pre- 

 sumably a result of the poor productivity in 

 1990. In 1992 productivity was poor again in 



