Peterson, S.H. Santolo, G.M. Ackerman, J.T. 20240220 spreadsheet n/a U.S. Geological Survey data release https://doi.org/10.5066/P9HJJ07G Gary M. Santolo Sarah H. Peterson Breanne Cooney C. Alex Hartman Mark P. Herzog Joshua T. Ackerman 20240424 publication The Wilson Journal of Ornithology vol. 136, issue 1 n/a Wilson Ornithological Society http://dx.doi.org/10.1676/23-00017 Eggshells of 13 waterbird species were divided in half longitudinally and the outer eggshell membrane was removed from one of the halves. Eggshell thickness was measured for both eggshell halves, both with and without the outer eggshell membrane. The eggshell membrane thickness was calculated by taking the difference between the two thickness measurements. The outer eggshell membrane thickness has not been empirically measured in many species; thus, we conducted this study to quantify the thickness of the outer eggshell membrane. We used these data to relate membrane thickness to egg morphometrics (egg length, egg width, and egg elongation) both within and among species. 2016 2022 ground condition Complete None planned southwestern United States -125.2441 -110.5664 41.9677 31.6534 ISO 19115 Topic Category biota USGS Thesaurus morphology (biological) None egg masses egg American avocet American coot Black skimmer Black-necked stilt California gull Caspian tern Double-crested cormorant Forster's tern Green heron Killdeer Pied-billed grebe Snowy plover Western grebe USGS Metadata Identifier USGS:65bd91bad34e18c6baf351da Integrated Taxonomic Information System (ITIS) Aves Birds U.S. Geological Survey 2013 Online Database https://doi.org/10.5066/F7KH0KBK www.itis.gov expert identifier Kingdom Animalia Subkingdom Bilateria Infrakingdom Deuterostomia Phylum Chordata Subphylum Vertebrata Infraphylum Gnathostomata Superclass Tetrapoda Class Aves TSN: 174371 None. Please see 'Distribution Info' for details. Questions pertaining to appropriate use or assistance with understanding limitations or interpretation of the data are to be directed to the individuals/organization listed in the Point of Contact section. U.S. Geological Survey, Western Ecological Research Center Data Manager mailing and physical

3020 State University Drive, Modoc Hall, Suite 4004

Sacramento CA 95819 USA 279-782-0904 gs-b-werc_data_management@usgs.gov This study was funded by the U.S. Geological Survey Ecosystem Mission Area’s Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology). Statistical analyses were done to examine the potential for outliers. Data were checked for ranges and duplication. Users are advised to read the rest of the metadata record carefully for additional details. No formal positional accuracy tests were conducted. No formal positional accuracy tests were conducted. We salvaged and collected eggs from 13 waterbird species as part of related contaminant studies during 2016-2022. In a laboratory, the exterior of each egg was cleaned and allowed to dry. Before egg dissection, egg length and width were measured using digital calipers. Eggs were dissected by cutting around the bottom of the air cell. After the egg contents were removed, the inside of the eggshell was gently cleaned. The egg was then cut lengthwise from the air cell to the sharp pole to divide the egg into approximately equal halves and the outer eggshell membrane was removed from one of the halves. Eggshells were then dried and subsequently measured using a Hall-effect thickness gauge with a 1.58 mm steel ball. The mean of replicate thickness measurements was quantified for each eggshell half and then the membrane thickness was calculated as the difference between the measurements for the two eggshell halves. Unknown EggshellMembraneThickness.csv Comma Separated Value (CSV) file containing data. Producer Defined Species Bird species American Ornithological Union American avocet Recurvirostra americana Producer defined American coot Fulica americana Producer defined Black-necked stilt Himantopus mexicanus Producer defined Black skimmer Rynchops niger Producer defined California gull Larus californicus Producer defined Caspian tern Hydroprogne caspia Producer defined Double-crested cormorant Phalacrocorax auritus Producer defined Forsters tern Sterna forsteri Producer defined Green heron Butorides virescens Producer defined Killdeer Charadrius vociferus Producer defined Pied-billed grebe Podilymbus podiceps Producer defined Snowy plover Charadrius nivosus Producer defined Western grebe Aechmophorus occidentalis Producer defined EquatorThicknessWithMembrane_mm The thickness of the eggshell half at the egg equator with the outer eggshell membrane intact, measured using a MagnaMike® 8600 thickness gauge (Olympus Scientific Solutions Americas Corporation) with a 1.58 mm magnetic measurement ball Producer Defined 0.1307 0.4965 millimeter EquatorThicknessWithoutMembrane_mm The thickness of the eggshell half at the egg equator with the outer eggshell membrane removed, measured using a MagnaMike® 8600 thickness gauge (Olympus Scientific Solutions Americas Corporation) with a 1.58 mm magnetic measurement ball Producer Defined 0.1205 0.455 millimeter CalculatedMembraneThickness_mm The calculated difference between the eggshell thickness measurements with and without the membrane Producer Defined 0.005 0.0955 millimeter EggMass_g Mass of the egg prior to dissection Producer Defined NA No Data Producer defined 5.92 77.27 grams EggLength_mm The length of the egg, measured using digital calipers Producer Defined NA No Data Producer defined 29.6 71.81 millimeter EggWidth_mm The width of the egg, measured using digital calipers Producer Defined NA No Data Producer defined 21.93 47.05 millimeter EggElongation The elongation of the egg, calculated as the egg length divided by the egg width Producer Defined NA No Data Producer defined 1.23 1.66 IncubationAge_days Embryos were aged to the nearest day when eggs were dissected Producer Defined NA No Data Producer defined 0 28 day ResearchGroup The research group that conducted the eggshell thickness measurements Producer Defined USGS-Ackerman The measurements were conducted in the research group led by Joshua T. Ackerman at the U.S. Geological Survey, Western Ecological Research Center, Dixon Field Station Producer defined Santolo The measurements were conducted by Gary M. Santolo Producer defined GS ScienceBase U.S. Geological Survey mailing address

Denver Federal Center, Building 810, Mail Stop 302

Denver CO 80225 United States 1-888-275-8747 sciencebase@usgs.gov Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. CSV https://doi.org/10.5066/P9HJJ07G None 20240425 Sarah H. Peterson U.S. Geological Survey, Western Ecological Research Center Wildlife Biologist mailing and physical

800 Business Park Drive, Suite D

Dixon CA 95620 USA 530-669-5088 sepeterson@usgs.gov FGDC Biological Data Profile of the Content Standard for Digital Geospatial Metadata FGDC-STD-001.1-1999