Study

Hatching Success and Predation of Bog Turtle (Glyptemys muhlenbergii) Eggs in New Jersey and Pennsylvania

  • Published source details Zappalorti R.T., Tutterow A.M., Pittman S.E. & Lovich J.E. (2017) Hatching Success and Predation of Bog Turtle (Glyptemys muhlenbergii) Eggs in New Jersey and Pennsylvania. Chelonian Conservation and Biology, 16, 194-202.

Actions

This study is summarised as evidence for the following.

Action Category

Protect nests and nesting sites from predation using artificial nest covers: Tortoises, terrapins, side-necked & softshell turtles

Action Link
Reptile Conservation

Relocate nests/eggs for artificial incubation: Tortoises, terrapins, side-necked & softshell turtles

Action Link
Reptile Conservation
  1. Protect nests and nesting sites from predation using artificial nest covers: Tortoises, terrapins, side-necked & softshell turtles

    A replicated, controlled study in 1974–2012 in 11 wetland sites in New Jersey and Pennsylvania, USA (Zappalorti et al. 2017) found that caged bog turtle Glyptemys muhlenbergii nests had lower predation rates compared to uncaged nests, but overall hatching success was not higher. Fewer eggs were predated in caged nests (6 of 97 eggs, 6%) compared to uncaged nests (82 of 161 eggs, 51%), but overall hatching success was not higher for caged nests (caged: 42 of 97 eggs, 43%; un-caged: 53 of 161 eggs, 33%). Cages of 1 cm wire mesh were installed over nests (61 cm high, 38 cm wide) and buried 8–15 cm into the ground. In June 1974–2012, twenty-seven nests in five wetlands were covered with cages, and 55 nests in 11 wetlands were left uncaged. Eggs were monitored for at least 8–9 weeks to record predation and hatching success.

    (Summarised by: William Morgan)

  2. Relocate nests/eggs for artificial incubation: Tortoises, terrapins, side-necked & softshell turtles

    A replicated, controlled study in 1974–2012 in a laboratory and 11 wetland sites in New Jersey and Pennsylvania, USA (Zappalorti et al. 2017) found that bog turtle Glyptemys muhlenbergii eggs incubated in a laboratory had higher hatching success than eggs left in wild nests. Hatching success was higher for eggs in the laboratory (74 of 91, 81% [numbers taken from table]) than for eggs in wild nests (caged nests: 42 of 97, 43%; uncaged nests: 53 of 161, 33%). Average hatching date was similar in the laboratory and field (30–31st August). Eggs were transferred from nests to a laboratory and incubated in plastic containers with humus from the wetland. Incubation temperatures ranged from 26–32°C during the day, and 17–24°C at night. In 1974–1993, a total of 91 eggs from five wetlands were transferred to the laboratory. In 1974–2012, a total of 258 eggs from 11 wetlands were monitored in 27 caged and 55 uncaged nests. Cages were 1 cm wire mesh and buried 8–15 cm into the ground. All eggs were monitored for at least 8–9 weeks to assess hatching success, and hatchlings from the laboratory were released at the original nest site within 5–10 days.

    (Summarised by: William Morgan)

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