The Arctic_shorebird_age_tool.xls was developed by Brooke Hill (updated in 2021 by Sarah Saalfeld) to estimate hatch dates, nest initiation dates, and nest incubation dates for nests with known hatch dates or initiation dates (i.e., date first egg is laid).
This tool can be found in the protocol folder.
This tool provides species-specific estimates for 10 species: American Golden-Plover (AMGP), Dunlin (DUNL), Pectoral Sandpiper (PESA), Red-necked Phalarope (RNPH), Red Phalarope (REPH), Ruddy Turnstone (RUTU), Semipalmated Sandpipe (SESA), Long-billed Dowitcher (LBDO), Buff-breasted Sandpiper (BBSA), and Western Sandpiper (WESA).
To use the tool, enter correct information for maximum number of eggs and either the hatch date or date first egg laid for a given species in appropriate cells (bold areas).
The tool will then estimate initiation date and incubation date when hatch date is known or incubation date and hatch date when initiation date is known.
The tool uses the following equations for its estimations:
Initiation dates: incubation date - number of eggs in nest + 1; assuming 1 egg is laid per day.
Incubation dates: hatch date - average incubation period for a given species when hatch date is known OR initiation date + number of eggs in nest - 1 when initiation date is known.
Hatch date: incubation date + average incubation period for a given species.
With the exception of Ruddy Turnstone and Buff-breasted Sanpdiper, average incubation periods were estimated from Weiser, E.L., S.C. Brown, R.B. Lanctot, H.R. Gates, K.F. Abraham, R.L. Bentzen, J. Béty, M.L. Boldenow, R.W. Brook, T.F. Donnelly, W.B. English, S.A. Flemming, S.E. Franks, H.G. Gilchrist, M.-A. Giroux, A. Johson, L.V. Kennedy, L. Koloski, E. Kwon, J.-F. Lamarre, D.B. Lank, N. Lecomte, J.R. Liebezeit, L. Mckinnon, E. Nol, J. Perz, J. Rausch, M. Robards, S.T. Saalfeld, N.R. Senner, P.A. Smith, M. Soloviev, D. Solovyeva, D.H. Ward, P.F. Woodard & B.K. Sandercock. 2017. Life-history tradeoffs revealed by seasonal declines in reproductive traits in Arctic-breeding shorebirds. Journal of Avian Biology 49 DOI: 10.1111/jav.01531. Incubation periods for Buff-breasted Sandpiper were based on Lanctot, unpublished data, while Ruddy Turnstones were based on Birds of the World (Rodewald and Schulenberg, eds. 20200. Cornell Laboratory of Ornithology, Ithaca, NY).
For detailed information on determining hatch and initiation dates see the Arctic Shorebird Demographics Protocol (Brown, S. C., H. R. Gates, J. R. Liebezeit, P. A. Smith, B. L. Hill, and R. B. Lanctot. Arctic Shorebird Demographics Network breeding camp protocol, Version 5, April 2014. Unpubl. paper by U.S. Fish and Wildlife Service and Manomet Center for Conservation Sciences. Available at https://www.manomet.org/sites/default/files/publications_and_tools/ASDN_Protocol_V5_20Apr2014.pdf).
The data providers have invested considerable effort in QA/QC, but it is possible that undetected errors remain. It is strongly recommended that careful attention be paid to the contents of the metadata file associated with these data to evaluate data set limitations, restrictions, or intended use. The originators of this dataset shall not be held liable for improper or incorrect use of the data described and/or contained herein.
