Headstarting Turtles: ­ A Different Perspective
By Chris Bogard ©2006

The purpose of this paper is to offer a different perspective on a recently published article titled "Headstarting Turtles ­ Is it a valid strategy for wildlife rehabilitators?" The author discredits headstarting past to present, but draws primarily from the historical shortcomings and failures of sea turtle projects. I would like to clarify that many critics of headstarting are not opposed to headstarting per se; they are opposed to it being used as the only conservation tool. One of the author¹s references makes this clear in the following: "The purpose of our study was to evaluate headstarting as a management tool for threatened turtle populations... We show that management efforts focused exclusively on improving survival in the first year of life are unlikely to be effective for long-lived species such as turtles" (Heppell et al., 1996). There is more to the headstarting debate and has the whole story been told? In order to analyze these questions, a more in depth look into the history of sea turtle programs is necessary.

History and Results

The sea turtle headstart project began in 1978 as a last ditch effort in response to the precipitous decline of turtles nesting at Rancho Nuevo, Mexico. At this time there were no requirements for the use of turtle excluder devices (TEDs) in shrimp trawls which allow escapement of incidentally caught sea turtles (Caillout, 2005). Turtles dying in these trawls is believed by some to have been the number one cause of mortality. The next 20 years that follow are extremely complicated due to different aspects of the project being phased out while other aspects received extensions. The criteria to assess the project¹s success/failure was rewritten several times. In September 1992, "the head start project was again re-evaluated as a two-part testable hypothesis: (1) Head-starting can produce Kemp¹s ridley juvenile sea turtles which are able to join the natural, wild population, and find their way to nesting beaches, procreate and hatch viable offspring of their own; and (2) head-started turtles demonstrate equivalent or superior biological fitness (defined as equal or better survival rates from egg to reproductive adult, and equivalent or better fecundity) when compared to wild Kemp¹s ridleys" (Caillout, 2005).

Are the results of this project "inconclusive at best"?  The first part of the hypothesis has been proven; the second part has not (Caillout, 2005; Meylan and Ehrenfeld, 2000; Fontaine and Shaver, 2005). Dr. Peter Pritchard has this to say about headstarting: "Theoreticians and pessimists should note that there is now, at last, good evidence that headstarting does work, and headstarted turtles can contribute to breeding populations. It has happened with Kemp¹s ridley (Pritchard, 1997) and with the Hood Island Galapagos tortoise (Cayot and Morillo). Indeed, it may have saved both of those taxa" (Pritchard, 1997).

Headstarting ­ Pros and Cons

The "critical early life stage" of hatchling turtles that Ms. Forrester expresses concern about is, possibly, what David Carroll calls the "nest to water journey".  In his book, Swampwalker¹s Journal, he tells the story of Wood, Blandings, Spotted and Painted turtles he followed after nest emergence. Instead of making a beeline for the water, they traveled circuitous routes. As to why they do this, Mr. Carroll writes: "I have come to think of the nest to water journey as a complex and critical component of an individual turtle¹s life, with profound implications for his or her species. My repeated encounters with turtles over the years leads me to believe that they never forget a place to which they have been, that they construct an ongoing map of all the wetlands and uplands they traverse. Hatchlings must begin mapping with their first steps from the nest."

Headstarting programs in conjunction with other conservation tools are currently being implemented. The Western Pond turtle, an endangered species in Washington, is being headstarted "where they appear to be surviving and successfully reproducing." The four strategies employed in this recovery project are captive breeding, headstarting, predation control and habitat protection (Fish and Wildlife Science, 2002). Results from a Western Pond turtle study in California reveal: "One frequent criticism of headstarting is that individuals are inappropriately accustomed to humans, and can therefore be easily captured and removed from the population. Since October 1996, we recaptured 44 of the 45 non-headstarted turtles a total of 80 times, and 24 of the headstarted turtles were recaptured 57 times. Recapture rates were not significantly different for headstarted vs. non-headstarted turtles" (Spinks et al, 2002).

The National Recovery Plan for Blandings turtles in Nova Scotia includes headstarting along with habitat protection and restoration. This particular program is "building on a pilot study showing that head started hatchlings survive and behave like wild hatchlings..." (Blandings Turtle Recovery Team, 2003).

Kathy Michell, a New York state Wildlife Biologist/Herpetologist and rehabilitator has been researching wood turtles with telemetry for 11 years.  Several of her headstarted turtles are close to reproductive age and have exhibited growth and behavior comparable to other sub-adults in the study population. (Pers. Comm).

After reading Mr. Carroll¹s nest to water journey, I am re-evaluating and revamping my release protocols for headstarted aquatic turtles. We can never get back the actual nest to water journey. We can release them in such a way that they experience an overland journey to the water.  Headstarting is not a panacea for declining populations, nor is it the conservation tool of choice in most cases if used exclusively. We are all aware of the fact that saving adults and the habitats they live in should be the focus.

Is Bigger Better?

In very simplistic terms, proponents of headstarting believe bigger is better; opponents believe this is theoretical. Recent field experiments conducted in Illinois are lending credence to the former. The purpose of the Illinois study was to "determine whether diurnal avian predation is a cause of size-specific survivorship of hatchling turtles during their migration from terrestrial nests to water." This was a continuation of a previous study which "documented significant directional selection favoring larger offspring during the post-emergence migration to water...Circumstantial evidence from these experiments and other studies...suggests that predation is the likely mechanism behind the observed size-specific mortality or recapture probabilities" (Janzen et al, 2000).  Red-eared slider hatchlings raised in captivity were divided into two groups. The control group allowed for avian predation. The predator-exclusion group excluded avian predation. The hatchlings were released 40 meters from the drift fence to allow for the overland journey. Hatchlings caught in the drift fence were divided into 3 categories: (1) recaptured alive, (2) fate unknown, (3) found dead. These three groups received between and within statistical analyses. The study concluded that avian predation kills smaller hatchlings significantly more often then larger individuals. The primary predators observed were red-winged blackbirds and common grackles. The researchers believe the cause could conceivably be gape limitations of the birds and/or larger hatchlings are faster then smaller ones.

Discussion

I have chosen not to respond to most of the reasons discouraging headstarting that are presented by the author. While they are very important husbandry and nutritional considerations, I feel these topics are more appropriate/relevant in a paper designed around turtle care-taking, not the legitimacy of headstarting.

It is important to know the life/reproductive strategy of turtles in order to understand the theoretical benefits of headstarting. Turtles depend on living long lives; their strategy is longevity. Longevity offsets high mortality rates for eggs and hatchlings. Ms. Forrester informs us, "In the wild, turtles have no maternal care and are capable of finding food, water, hiding places, and hibernation spots the moment they emerge from the nest." This is true, but I would like to stress that it is the fortunate hatchling that finds their way to food, water, etc and the second year of life. It is precisely because they receive no parental care that egg and hatchling mortality is so high, and turtle literature is replete with this very sad fact. Many turtle lives are cut short by road mortality and these are the cases most frequently encountered by rehabbers.

Two of the primary criticisms against headstarting are that it does not address the root causes of declining populations and it is highly manipulative. For rehabbers, neither of these criticisms is true. Our emphasis is always on saving the injured adult¹s life. We are not using headstarting as a primary conservation strategy. Headstarting by rehabbers is not highly manipulative. We are not unearthing eggs laid in the wild, nor are we keeping wild turtles in captivity for breeding purposes. I can speak only for myself, but I am incubating eggs primarily from dead females which leads into the root of the matter ­ why headstart these turtles versus release shortly after hatching?

Every dead female¹s progeny is possibly the last chance to return a portion of her unique genetic information back to the population she came from. To assume she has no surviving offspring isn¹t unreasonable considering the predation pressures on eggs and hatchlings. Except for Snappers, turtle clutches are small and yield few individual possibilities for survival to adulthood. To insure, as best we can, that some of her descendents will survive and add to or maintain the genetic diversity of her population, headstarting is a much better insurance policy. Admittedly, I am assuming a lot here; therefore, the next question I ask myself is ­ am I harming the population? The author states that headstarted turtles may carry pathogens and introduce disease to wild populations. I¹m assuming this is because they are in captivity longer. Where are these potential pathogens coming from and why are headstarted turtles a more likely vehicle than our overwintered adult turtles? The possibility of headstarted turtles carrying pathogens into wild populations was a concern in the early days of the sea turtle program. Poorly funded and supported operations were plagued with serious problems. Because of crowding, diseases such as chlamydiosis, gray-patch, necrotic skin lesions and sudden hatchling death syndrome were well documented (Meylan and Ehrenfeld, 2000). Mitigating cross-contamination (source of pathogens?) is the responsibility of each individual rehabilitator and is a concern across all age classes of all species. Second, because we are releasing into the population the mother came from (this is critical) any genetic information that may confer a specific adaptation to a particular environment has not been disrupted.

Many of the protocols employed and decisions made by wildlife rehabilitators for all our various wildlife species are done so without the benefit of "a controlled research study conducted within scientific parameters." The decisions we make are based on knowledge of many different disciplines and some scientific research to guide us. Controversial issues abound such as whether or not to release a raptor that is sight impaired in one eye. Headstarting is one of these controversial issues.  Determining the successes or failures of headstarting in chelonians is a long process, since survival to adulthood and eventual reproduction will be a major criteria in making those determinations.  Many research and conservation efforts are now reaching that goal with excellent results.  Turtles are going to need all the conservation tools that we can provide to help ensure their survival. Unless a decision/protocol/strategy collapses in the face of scientific evidence, or just common sense, it is inappropriate to posit "there is no justification" to a particular strategy. Wildlife rehabilitation is full of personal decisions based on current research, and research is constantly changing knowledge.

Literature Cited and References

Belzer, B. (1996).  Box Turtle Repatriation in Northwestern Pennsylvania.  Box Turtle Research & Conservation Newsletter # 4: 12-13.

Belzer, W.R., S. Seibert, and B. Atkinson. 2002. Putative Chipmunk Predation of Juvenile Eastern Box Turtles.  Turtle and Tortoise Newsletter. 5:8-9.

Breisch, A. 1997. The Status and Management of Turtles in New York. (editor) T.F. Tyning, Status and Conservation of Turtles in the Northeastern United States. Mass Audubon Society. Serpent¹s Tale Publishing, Lanesboro, MN p.11-14.

Brooks, R.J. 1997. Dynamics of a northern population of snapping turtles: How can long-lived species be conserved? (editor) T.F. Tyning, Status and Conservation of Turtles in the Northeastern United States. Serpent¹s Tale Publishing, Lanesboro, MN p.31-33.

Burbridge, A.A. & Kuchling, G. (1994). Western Swamp Tortoise Recovery Plan. Wildlife Management Program, No. 11, Department of Conservation Land Management.
Available online at Environment Australia (September, 2002).

Cayot, L. J. and G. E. Morillo.  1997.  Rearing and repatriation of Galápagos tortoises: Geochelone nigra hoodensis, a case study.  In: J. Van Abbema (ed.), Proceedings: Conservation, Restoration, and Management of Tortoises and Turtles‹An International Conference, pp. 178­183.  July 1993, State University of New York, Purchase.  New York Turtle and Tortoise Society, New York.

Fontaine, C., Shaver, D., 2005. Head-Starting the Kemp¹s Ridley Sea Turtle, Lepidochelys Kempii, at the NMFS Galveston Laboratory, 1978-1992: A Review.
Chelonian Conservation and Biology Vol. 4, No. 4: 843.

Heppell, S.S., Crowder, L.B., Crouse, D.T., 1996. Models to Evaluate Headstarting as a Management Tool for Long-Lived Turtles. Ecological Applications, Vol. 6, No.2: 556-557.

Janzen, F.J., Tucker, J.K., Paukstis, G.L., 2000. Experimental analysis of an early life-history stage: avian predation selects for larger body size of hatchling turtles. J. Evol. Biol. 13: pp. 947-954.

Meylen, A.B. Ehrenfeld, D., 2000. Conservation of Marine Turtles. Turtle
Conservation (Klemens, M.W.,ed), pp.113-114. Smithsonian Institute Press, Washington and London.

Michell, K. and R.G. Michell. 1999. Translocation, rehabilitation and headstarting of wood turtles Clemmys insculpta in New York State. Abstracts of the 1999 SSAR Joint Meeting at Penn State.

Pritchard, P.C.H., 1997. Conservation Strategies-An Overview: Implications for
Policy. In: J. Van Abbema (ed.), Proceedings: Conservation, Restoration, and Management of Tortoises and Turtles‹An International Conference, p. 470.  July 1993, State University of New York, Purchase.  New York Turtle and Tortoise Society, New York.

Spinks, P.Q., Pauly, G.B., Crayone, J.J., Shaffer H.B., 2003. Survival of the western pond turtle (Emys marmorata) in an urban California environment. Biological
Conservation 113., pp. 257-267.

Web References

Blandings Turtle Recovery Team. 2003. National Recovery Plan for the BLANDING¹S TURTLE (Emydoidea Blandingii) Nova Scotia Population.
www.speciesatrisk.ca/blandings/Blandings_Turtle_Recovery_Plan_Jan2003.pdf

Caillouet, C.W. Jr., 2005. Wild and Head-started Kemp¹s Ridley Nesters, Eggs, Hatchlings, Nesting Beaches and Adjoining Nearshore Waters in Texas Should Receive Greater Protection. Marine Turtle Newsletter 110:1-3. www.seaturtle.org/mtn/archives/mtn110/pl.shtml.

Pritchard, P.C.H., 1997. A new interpretation of Mexican ridley population trends. Marine Turtle Newsletter 76:14-17. www.seaturtle.org/mtn/archives/mtn76/mtn76p14.shtml

Washington Department of Fish and Wildlife. Western Pond Turtle Recovery Plan, 2002. Fish and Wildlife Science.  http://wdfw.wa.gov/science/articles/pond_turtle/