<?xml version='1.0' encoding='utf-8'?>
<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>Joshua T. Ackerman</dc:contributor>
  <dc:contributor>C. Alex Hartman</dc:contributor>
  <dc:contributor>Andrew C. Greenawalt</dc:contributor>
  <dc:contributor>Michael L. Casazza</dc:contributor>
  <dc:contributor>Mark P. Herzog</dc:contributor>
  <dc:creator>Sarah H. Peterson</dc:creator>
  <dc:date>2024</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;Waterfowl population recruitment is sensitive to duckling survival. We quantified predator types and survival rates for&amp;nbsp;&lt;/span&gt;&lt;i&gt;Anas platyrhynchos&lt;/i&gt;&lt;span&gt;&amp;nbsp;(Mallard) and&amp;nbsp;&lt;/span&gt;&lt;i&gt;Mareca strepera&lt;/i&gt;&lt;span&gt;&amp;nbsp;(Gadwall) ducklings in one of the largest brackish water marshes in western North America (Suisun Marsh, California) using 556 radio-tagged ducklings from 284 broods tracked during the 2016 to 2019 breeding seasons. Overall, 78% of ducklings died and 84% of mortalities occurred &amp;lt; 7 days after hatch. After hatching in upland fields, survival was greater for broods that hatched closer to flooded wetlands; broods had a ≥ 75% chance of surviving the move from the nest to water when nests were located ≤ 140 m from the nearest wetland and ≤ 50% chance of surviving when nests were located ≥ 970 m from the nearest wetland. Predation accounted for 91% of mortalities and was attributed to mammals (27.6%), birds (22.0%), snakes (4.4%), and unknown predators (46.0%).&amp;nbsp;&lt;/span&gt;&lt;i&gt;Anas platyrhynchos&lt;/i&gt;&lt;span&gt;&amp;nbsp;survival to fledging (54 days) was only 3.2% and 0.9% during 2 drier years and 11.7% and 16.7% during 2 wetter years.&amp;nbsp;&lt;/span&gt;&lt;i&gt;Mareca strepera&lt;/i&gt;&lt;span&gt;&amp;nbsp;survival to fledging was 9.4% to 11.2% among years. Daily survival rates for ducklings generally increased with the amount of flooded wetlands within 0.5 km (&lt;/span&gt;&lt;i&gt;A. platyrhynchos&lt;/i&gt;&lt;span&gt;) and 1.0 km (&lt;/span&gt;&lt;i&gt;M. strepera&lt;/i&gt;&lt;span&gt;) of the nest at hatch. Additionally, survival rates increased with duckling age and body mass at hatch for both species and decreased with hatch date for&amp;nbsp;&lt;/span&gt;&lt;i&gt;A. platyrhynchos&lt;/i&gt;&lt;span&gt;&amp;nbsp;but not&amp;nbsp;&lt;/span&gt;&lt;i&gt;M. strepera&lt;/i&gt;&lt;span&gt;, which may be partially due to the earlier onset of&amp;nbsp;&lt;/span&gt;&lt;i&gt;A. platyrhynchos&lt;/i&gt;&lt;span&gt;&amp;nbsp;nesting. For ducklings that survived the initial move to water, survival rates were negatively correlated with salinity and this effect was more pronounced for younger ducklings.&amp;nbsp;&lt;/span&gt;&lt;i&gt;Anas platyrhynchos&lt;/i&gt;&lt;span&gt;&amp;nbsp;survival to 7 days post hatch decreased by 9.1% (wetter year) to 31.4% (drier year) when ducklings were in 12 ppt water (99th quantile of cumulative salinity concentrations experienced by ducklings) versus 0.5 ppt water.&amp;nbsp;&lt;/span&gt;&lt;i&gt;Mareca strepera&lt;/i&gt;&lt;span&gt;&amp;nbsp;survival to 7 days decreased by 7.4% when ducklings were in 12 ppt vs. 0.5 ppt water. Our results suggest that maintaining a network of low salinity wetlands within 1 km of upland nesting sites would likely improve duckling survival rates, especially during the critical 7-day period after hatch.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1093/ornithapp/duae017</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Oxford Academic</dc:publisher>
  <dc:title>Duckling survival increased with availability of flooded wetland habitat and decreased with salinity concentrations in a brackish marsh</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>