Conducting nesting bird surveys is an important way to monitor bird populations and understand their breeding success. This allows conservationists to identify declining species and habitats in need of management. There are several things to know before conducting a nesting bird survey:
When to Survey
Most nesting surveys are conducted during the breeding season, which is spring and early summer for most bird species. The exact timing will depend on your region and target species. Surveys usually begin just before or at the start of nesting and may continue through the nesting cycle into early fledging.
Getting Permits
You may need permits or permission to conduct surveys, especially on public or protected lands. Research permit requirements for your survey locations. Federal and state agencies often have special regulations regarding protected nesting birds like eagles, hawks, owls, herons, and other species.
Selecting Sites
Choose sites that represent the habitats you want to survey. This may include forests, fields, wetlands, coastal areas, or urban zones. Make sure you have landowner permission to access any private property. Prioritize areas known to support key nesting species of interest.
Equipment Needed
Bring all required equipment into the field:
– Binoculars
– Bird field guide
– Data sheets
– Pencils/pens
– Flagging or tree marking tape (optional)
– Small mirrors or angled viewers for seeing inside nests (optional)
Conducting Point Counts
Point counts are a common nesting bird survey method. This involves observing birds from set points within the habitat:
Selecting Count Points
– Space points at least 250 meters apart to avoid double-counting birds.
– Mark point locations on a map and GPS device. Clear trails between points if needed.
– Use 8 to 12 points for a standardized survey. More points can be added in core habitat.
Count Duration
– Spend 5 to 10 minutes observing birds at each point.
– Be consistent across points and repeat visits. 10 minutes provides the most thorough data.
Timing
– Conduct all points in the morning, starting 30 minutes before sunrise.
– Avoid windy or rainy conditions.
– Repeat counts at the same time frame across multiple visits if possible.
Observations
– Record every bird seen or heard from the point.
– Note breeding behaviors like carrying nest material, nest building, territorial acts, fledglings, etc.
– Use distance estimates to avoid double counting birds.
– Watch for simultaneous singing birds indicating multiple territories.
Mapping Territories
Map singing, calling, and observed territories for each species based on your point count data. This helps estimate population density and distribution.
Territory Mapping Tips
– Map clusters of point detections as potential territory centers.
– Draw a territory circle in areas consistently occupied by individuals.
– Size territories based on species norms and habitat – ex: 50 meter radius for warblers in forests.
– Overlapping territory edges are often indicative of mated pairs.
– Leave gaps in continuous habitat unmapped if no birds were detected there.
Searching for Nests
Active searching for nests can provide additional breeding data but is very time intensive. Follow these tips when searching for nests:
When to Search
– Late in incubation period when nests are easiest to find.
– Avoid early nesting stage when eggs or young are vulnerable.
– Search again right before expected fledging.
Nest Finding Tips
– Watch adult behavior like repeatedly visiting sites.
– Follow adults carrying nest material.
– Check likely nest sites in vegetation and cavities.
– Use pole-mounted mirrors to see inside bushes and trees.
– Mark nests discreetly with flagging on branches 10 meters away.
Data to Record
For each nest found, record:
– Nest ID code
– Location coordinates
– Height above ground
– Nest tree species
– Nest stage (building, incubating eggs, nestlings, etc)
– Adult species using nest
Monitoring Nests
Regularly monitor marked nests to track breeding success:
Frequency
– Check open cup nests every 3-4 days.
– Monitor enclosed nests like cavities weekly.
Data to Record
– Stage of eggs/young on each visit.
– Any nest failures or predation events.
– Final number of chicks fledged.
Visiting Nests
– Be quick and minimize disturbance. Don’t linger.
– Don’t approach if adults seem agitated.
– Avoid visiting in very wet or cold weather.
Analyzing and Reporting Data
Compile survey results to estimate population sizes, trends, and productivity:
Occupancy Rates
– Calculate % points occupied per species.
– Compare occupancy across habitats and years.
Territories
– Estimate number of probable territories per species.
– Compare territories across habitats and years.
Nest Success
– Calculate % nests successful per species.
– Determine average number of young fledged per nest.
– Compare reproductive success across habitats and years.
Recommendations
– Identify declining species that may need conservation action.
– Detail habitat management recommendations based on the data.
– Suggest expanded survey locations and methods to improve future surveys.
Point | Species | Number Detected | Breeding Cues |
---|---|---|---|
1 | Red-eyed Vireo | 2 | Carrying nesting material |
1 | Black-capped Chickadee | 1 | None observed |
2 | Ovenbird | 1 | Singing |
Nest ID | Species | Nest Outcome | Number Fledged |
---|---|---|---|
RBWO-01 | Red-bellied Woodpecker | Successful | 3 |
EABL-02 | Eastern Bluebird | Predated | 0 |
Conclusion
Conducting thorough nesting bird surveys requires careful planning, consistent field methods, and attention to detail. The data gathered provides vital information on breeding bird populations that can guide conservation efforts. Following protocols for selecting sites, conducting point counts, mapping territories, finding and monitoring nests, and analyzing the data will produce quality results. Make sure to acquire any required permits and permissions before surveying protected areas or species. With sound field techniques, nesting bird surveys generate data integral for understanding breeding bird ecology and implementing management strategies.