Banders without Borders

1. Banders without Borders Implementing a large-scale cooperative mark-resight study

2. Background • Growing interest in AMOY research • Loosely organized cooperative effort over the past several years • Good communication among researchers – listserver, central website (http://www4.ncsu.edu/~simons/AMOY Research.htm) • Collaboration has allowed us to think through questions as a group and converge on solutions • We have an emerging consensus on: • Winter and summer trapping methods • Organized color-banding scheme • Coordination with band supplier, banding codes • Age of banding for chicks

3. Background • Success of the working group demonstrated with the coastwide aerial/boat/ground survey in 2002-2003 • Obtained accurate and precise information on population size, distribution, and habitat use of wintering AMOY

4. Background • Coordinated banding scheme • Triple layer size 6 Darvic color bands engraved with a 2-digit alphanumeric code • Supplier: Robin Haggie, HAGGIE ENGRAVING • Codes: 0,1,….9 A C E F H J K M N P R T U X Y • Removed to reduce error - B D G I L O Q S V W Z • 625 Possible Combinations • Current state colors • Massachusetts – Yellow with Black codes • Virginia – Black with White codes • North Carolina – Green with White codes • South Carolina – Blue with White codes • Georgia – Red with White codes • Future states • White with Black codes • Orange with Black codes • Maroon with White codes

5. Background • Band Placement • Discussion over whether to use a single engraved color band or two identical bands, one on each leg • Advantages of single band: • Costs less • Less potential risk to bird • Faster banding time • Advantages of duplicate bands: • Greater probability of detecting bands • Bands can be read from either leg, increasing resighting rate • Better return for equal banding effort • Over 200 birds in four states banded this year with duplicate bands • No injuries or band difficulties seen • Based on my experience, and reports from Georgia and Massachusetts, the duplicate bands improve resighting potential • Return on investment seems to justify the small additional cost • Recommendation: Continue using duplicate bands

6. Background • Color-Banding began in North Carolina in 1999 • South Carolina and Georgia began banding in 2001 • Virginia and Massachusetts started in 2003 • Currently looking at expanding the effort into New Jersey

7. Background • Each project has maintained a re-sight database for their birds • At NCSU I am building a central database for all inter-state resightings • This database currently has 633 banding records from 5 states with 46 inter-state resights of individual birds

9. Mark-Resight • Poised to begin a designed resight effort • A carefully planned resight study has significant advantages over marking and waiting for opportunistic recoveries • Control or remove bias for quantitative analysis • Ensure equal probability of detection • Allocate effort across potential habitat • Result is unbiased survival estimate

10. Mark-Resight • Important to have quantitative, defensible information • Results from opportunistic resighting can be highly biased • Example: Consider two wintering habitat types; shell rakes and marsh roosts • Birds on shell rakes are easier to locate and bands are easier to see • These birds are more likely to get counted and have their bands reported than the birds in the less visible marsh habitat • Result will be a distorted view of the population if the visibility bias is not accounted for

12. Mark-Resight • Differential access is another source of bias. Birds at remote roosts may be sampled infrequently or not at all. • Sampling at the appropriate scale is crucial • The entire Southeast region must be covered in a relatively short time window to avoid confounding mortality estimates with emigration

13. Mark-Resight • Ultimately we want to control bias and avoid uncertainty and heterogeneity in detection probabilities • I will take an adaptive approach to implementing this project • Design sampling protocol • Conduct surveys • Model data, identify sources of bias • Adjust sampling approach • With this approach our estimates will improve over time, and we can evaluate sources of uncertainty in the data • Excellent tools are available for model selection. I will use Program Mark to chose between models and pinpoint sources of bias

14. Mark-Resight: Objectives: • Initiate a multi-year cooperative mark-resight study • Build a series of demographic models with good estimates of survival for adults, sub-adults and juveniles • Explore the potential for more complex models that incorporate movement and dispersal

15. Mark-Resight: Survey Plan • Identify existing roost sites • Largely known from the recent aerial survey and from annual state counts in Virginia and South Carolina

16. Mark-Resight: Survey Plan • Survey routes will be designed to cover all known roosts between mid-November and January • Full state surveys planned in New Jersey, Virginia, North Carolina, South Carolina, and Georgia. • Currently working on setting up Florida surveys.

17. Mark-Resight: Survey Plan • Survey Protocol under development • Roosting flocks will be surveyed within 2 hours of high tide • Flocks will be scanned for banded birds – we will investigate whether standardized digiscoping will provide a more accurate record • Flock size, age ratio, GPS location will be recorded for each flock

18. Conclusion • Long term goal is to develop an adaptive, long term program to monitor the distribution, abundance, and demographic rates of AMOY along the eastern seaboard • Result will be a better understanding of the demographics, resource use, and movement of American Oystercatchers • Modeling will show population structure and trend and identify critical breeding productivity levels • Information will be directly applicable to setting management goals and policies • By definition, this is a collaborative project • Any publications would be a joint effort by working group collaborators