Friends of Hakalau Forest
National Wildlife Refuge
March 2019 Newsletter
Presidents' Perch March 2019

J.B. Friday
President, Friends of Hakalau Forest National Wildlife Refuge
In This Issue



Research in the Refuge

Toxoplasmosis in Cats, Wildlife, and the Environment

We don't value what we don't know.

Hakalau is unusual among wildlife refuges in that is isn't open to public access. I grew up near a wildlife refuge, the Great Swamp NWR in New Jersey, that had a visitor center and entry only a few blocks from my house. You could drop by for a jog after work or an early morning outing before your day began. School trips to the Refuge were easy and frequent. Not so for Hakalau, where getting there requires attending a volunteer day and driving hours from town, much of it on rough roads.
One of the most important thing your Friends organization does is help connect the local community with the Refuge. At our annual half-day meeting earlier this month, your Board planned several way to connect you, our members, and our local Hawai'i Island community with the Refuge.

First are these newsletters such as the one you are reading. We have moved to the digital age and are getting out four issues a year. In addition to goings-on on the Refuge and with the Friends, we are publishing articles from scientists working on conservation issues in Hawaii, such as the article by Steve Hess in this issue. Since these are posted on our website, we have found that people are sharing them widely.

Speaking of websites, we have a new design in the works which will finally be able to accept membership payments and donations on-line.
Locally, we sponsor a series of community talks in Hilo on various conservation topics. Some feature work being done on the Refuge, but others, such as our talk last January by Leilani Fowlke on seabird relocation, feature our colleagues working in other ecosystems.
Most importantly, we are working with Tom Cady, our new Refuge Manager, and the Refuge staff and interns to plan for volunteer trips up to the Refuge for Friends members. As always, these trips will include some service such as working in the greenhouse or outplanting trees along with opportunities to bird and just experience the Refuge.
I hope to see many of you at these and other events and especially up on the Refuge. Mahalo for your support.

Manager's Report

Tom Cady
Big Island National Wildlife Refuge Complex Project Leader

Aloha everyone!

Well, it has been just over a month since I started my position as the new Project Leader for Hakalau NWR and I feel like things are off to a good start. We are almost caught up with addressing administrative issues brought on by the recent government shutdown and are back to focusing on resource management at Hakalau. I have been working closely with staff to gain a good understanding of the status of ongoing projects, refuge issues and needs, and visiting with some of the numerous researchers, partners, and stakeholders that have an interest in Hakalau. I haven’t been able to get over to the Kona unit yet, but my wife and I volunteered for a weekend up at the refuge helping Baron pot up over 800 native plant seedlings. It was great to get my hands dirty working at the refuge again! We even ran into Jack Jeffrey who was escorting a Japanese film crew there to film the resident birds and share our story with the world. It will be wonderful to see the final product – maybe by the end of the year.
I have a number of items I am eager to explore and address at the refuge in the coming months and years. Some of them may be lofty dreams, but others are certainly attainable. As most of you probably know, we have a very small staff and modest budget. Together with our partners, we face what I would consider enormous challenges and issues that are affecting the refuge and its resources. In light of this reality and some of our overriding governmental requirements, I believe we should invest some time reflecting on what we have accomplished in the past and where we are at right now so that we can plan out where we are heading in the future. I will be working with our staff over the coming months to better define this visioning process. In the meantime, I don’t foresee any major changes to our normal activities like ungulate removal, fence maintenance, weed control, bird monitoring, and plant propagation and out planting. Also in the very near term, I will work with staff to compile a list of ‘needs’ that our friends and volunteers can help us accomplish on the ground. It is so obvious to me how important our Friends, partners and volunteers are to attaining our management objectives at Hakalau, so thank you, thank you, THANK YOU for your support. I look forward to working with the Friends to continue to meet the many challenges facing the refuge now and into the future.

Refuge Art Contest

A new Hakalau NWR T-Shirt design is in the works! We thought it would be fun to find a new design after using the current design for nearly 20 years. Hakalau NWR, in collaboration with Hawaii Nei, is calling all artists. We plan to have two cohorts of local artists visit the refuge this April in search of inspiration. Artists must sign up for a refuge "tour" where they will visit the refuge to learn about Hakalau Forest NWR, plant native trees, and bird watch. Their refuge visit will end with time to observe and absorb the forest, be inspired, and collect images and ideas for the artwork they intend to submit to the contest. Refuge staff will cast their votes in early July and the first place selection will be featured on the new refuge T-shirt, expected to be printed and available by the end of August 2019.

Angela Beck, masters candidate
Tropical Conservation Biology and Environmental Studies, UH Hilo

One of the defining characteristics of songbirds is their songs—complex, learned vocalizations generally used to defend territory or attract mates. A great deal of research has been done on birdsong around the world, but until recently, very little work had been done on the vocalizations of Hawaiian forest birds. I became interested in studying ‘i‘iwi because their vocalizations are highly variable compared to some other Hawaiian songbirds such as Hawai‘i ‘amakihi and Hawai‘i ‘elepaio, and because it seemed likely that both male and female ‘i‘iwi sing, which is not the case for all songbirds.
My goal was to catalog and describe the ‘i‘iwi repertoire, determine the size of an individual ‘i‘iwi’s repertoire and how much variability exists between individuals, and compare male and female ‘i‘iwi to determine whether certain vocalizations or aspects of vocal behavior were characteristic of one sex or the other. During the spring (‘i‘iwi breeding season) of 2015 and 2016, I stalked ‘i‘iwi at two banding sites in the Hakalau Forest NWR. I recorded birds that had been captured by the Hawai‘i Forest Bird Demography Project and given unique combinations of colored leg bands, so that I was able to identify them as individuals and as male or female. Male and female `i`iwi look nearly identical to the human eye and must be sexed by careful measurements of their size or by the presence of certain features such as a brood patch on nesting females or a swollen cloaca on breeding males. Then I spent many months examining spectrograms of the recordings—graphical representations displaying vocalizations as squiggly lines, with frequency in kilohertz on the y-axis, time in seconds on the x-axis, and power (loudness) displayed using a spectrum of color.
‘I‘iwi song is composed of smaller units called syllables, collections of one or a few notes in unique, identifiable patterns. An ‘i‘iwi strings together a selection of syllables in a nearly random order to construct each song. From a set of thirteen ‘i‘iwi (seven males and six females), I was able to identify 182 unique syllables. The size of an individual repertoire was highly variable, with an average of ten syllables, and up to 68 syllables for one male. I confirmed that both male and female ‘i‘iwi sing, but rather than finding that certain syllables or vocal behaviors were associated with one sex or the other, I found that each ‘i‘iwi of both sexes were highly individualistic, with different repertoire sizes, repertoire content, and vocalization rates. I was excited to observe and record duetting, a special behavior in which a mated pair sings together, and which in the case of ‘i‘iwi may present a stronger territorial defense and strengthen the pair-bond between mated birds. My greatest take-away is that a lot more research is needed to fully understand the vocal behavior of these individualistic and vocally-talented birds!

Steven C. Hess
US Geological Survey, Pacific Island Ecosystems Research Center
Many factors have contributed to the decline and extinction of birds in Hawai‘i, not the least of which has been introduced mammalian predators like rats, mongooses, and cats. These predators take eggs, kill nestlings, or nesting adults, but are also sources of diseases that kill birds [1]. One such disease known as toxoplasmosis can cause severe developmental disabilities and occasional mortality in humans but can also have lethal consequences for marine mammals. The infectious agent of the disease, Toxoplasma gondii , is a protozoan, a single-celled organism which behaves like an animal. It is considered a parasite, causing infection directly rather than by producing toxins. It is a zoonosis because it is a disease of animals that can also be transmitted to humans. The source of toxoplasmosis was for many years a mystery because of its complex life history, apparently only infecting people who ate raw or undercooked meat. Then in 1970, hardy, thick-walled environmentally resistant spores called oocysts in cat feces were discovered to contaminate the environment and lead to infection when ingested [2] . Soon after, toxoplasmosis was found to be widespread on Pacific islands with domestic cats ( Felis catus ) but not on islands without cats [3]. It was eventually shown that only cats –regardless of whether they are domestic or wild species– can support sexual reproduction of this parasite, and thereby serve as the definitive host of the disease [4]. Other warm-blooded animals, most commonly rodents, can also carry the parasite but are intermediate hosts, where it can only reproduce asexually in body tissues. The life cycle of T. gondii is completed in turn when an uninfected cat consumes an infected intermediate host, thereby ingesting tissue cysts and initiating the sexual cycle of the parasite again.
The overall percentage of cats that have been infected with T. gondii can range from 5.4–74.2% depending on location and the diagnostic method used [5]. These methods typically report seroprevalence, which is based on immunological responses and presence of antibodies in blood. Specific antibodies can be used to further differentiate chronic infections from active infections; IgG antibodies indicate past exposure and IgM antibodies indicate active or recent infection. Seroprevalence is related to age because the chance of infection usually increases over the course of a lifetime. Feral cats on Mauna Kea during 2002–2004 had an overall exposure of 37% while only 7% had active infections [6]. On Kaho‘olawe, 27% of cats were exposed in 2002, but no evidence of active infections was found [7]..  T. gondii seroprevalence in cats may vary over time and between islands because of differences in the availability and type of intermediate hosts that cats consume as prey.
Many terrestrial mammals are intermediate hosts of the parasite. Although some intermediate hosts may never be consumed by cats, they may sometimes be consumed by people. Known intermediate hosts include feral pigs ( Sus scrofa) and mouflon sheep ( Ovis musimon), both popular game mammals in Hawai‘i [8]. The number of intermediate hosts that may be infected by T. gondii is clearly dependent on the presence of cats; for example, 18.2% of pigs from mainland Georgia where cats are abundant were exposed to T. gondii, but less than 1% of pigs were exposed on nearby Ossabaw Island, where only a single cat lived [9]. Other work also supported this finding [10]. Interestingly, one behavioral effect of T. gondii on rodents is to make them less risk-averse to predators, thereby increasing the likelihood that they will be consumed by cats to complete the life cycle of the parasite [11]. 
Numerous studies have addressed the effects of T. gondii on humans as a common intermediate host. The effects of infection with T. gondii in humans are often asymptomatic or mild in adults except for those with compromised immune systems, for whom the disease may be fatal. Symptoms are often mistakenly attributed to more common illnesses. Consequently, it is largely underdiagnosed in humans; however, infection during pregnancy can result in severe developmental problems in fetuses including blindness and lifelong mental disabilities [12]. The overall age-adjusted seroprevalence in the U.S. from 1988–1994 was 22.5% but was higher in the northeast (29.2%) than in the south (22.8%), midwest (20.5%), or west (17.5%) [13]. Risk for T. gondii infection increased with age and was higher among persons who were foreign-born, persons with lower educational levels, those who lived in crowded conditions, and those who worked in soil-related occupations.
Birds can also be intermediate hosts, and populations that have been isolated from cats for long periods may be naïve to infection, making then highly susceptible to mortality. Birds that have been infected and killed by T. gondii include the critically endangered ‘Alalā [14] ( Corvus hawaiiensis ), the endangered Nēnē [14] ( Branta sandvicensis ), Red-footed Booby ( Sula sula ), and Erckel’s Francolin [15] ( Pternistis erckelii ), a common gamebird. While feral cats were not directly observed killing ‘Alalā in the 1990s near what is now the South Kona Forest Unit of the Big Island National Wildlife Refuge Complex, T. gondii is known to have killed at least five young birds that had been released into the wild [14]. It is unclear how ‘Alalā encountered the parasite, although they may have acquired it through direct contact with cat feces, from soil containing oocysts shed by cats, or by depredating or scavenging carcasses of intermediate T. gondii hosts such as rodents [14].  T. gondii is known to be an important cause of mortality in Nēnē [16]. Terrestrial animals, however, are not the only ones affected .
From Land to Sea

Cats may shed millions of T. gondii oocysts in feces which can lead to substantial environmental contamination [17] (Figure 1). Oocysts may survive for months or years even in seawater or 2% sulfuric acid [18]. In cat colonies at the Mānoa campus of the University of Hawai‘i, T. gondii DNA was detected in 5% of fecal samples amplified by polymerase chain reaction, and at Ka‘ena Point on O‘ahu, it was detected in 22.2% of fecal samples [19]. Although the method was not able to detect it in 120 soil samples at UH Mānoa, T. gondii normally occurs in 5.4–17.8% of soil samples in temperate environments where cats are present [20]. In the area of Morro Bay, California, the environmental burden was estimated to be 94 to 4,671 oocysts per square meter based on 107.6 metric tonnes of cat feces deposited outdoors annually [21]. Flowing water may transport oocysts in runoff from land to streams, storm water drainages, or municipal sewage systems into marine environments where they can release sporozoites, which are motile cells of the parasite [18]. Thus, T. gondii represents a land-based pathogen that can pollute nearshore marine ecosystems and infect a wide variety of animals in this environment. 

T. gondii is known to infect seals [22], penguins [23], and several species of cetaceans, including spinner dolphins ( Stenella longirostris ) in Hawai‘i [24]. In California, sea otters ( Enhydra lutris ) are highly susceptible to mortality from T. gondii i nfection, which occurred in 52% of carcasses discovered on beaches [25] The leading known cause of death of the endangered Hawaiian monk seal ( Monachus schauinslandi ) is T. gondii infection with 11 documented cases [26], [27]. . Because carcasses of animals that die in the wild most often remain undiscovered or in poor condition, the true extent of infection and mortality caused by the parasite is difficult to determine and is likely underestimated.
Depredation in Addition to Infection

The effects of T. gondii is only one factor associated with the protection and restoration of native Hawaiian birds; depredation is an equal or greater consideration in many cases. There is an increasing amount of documentation of endangered species depredation by feral cats from remote cameras. Remains of endangered birds have long been associated with feral cats, but direct evidence of depredation was lacking, therefore scavenging could not be discounted. Direct evidence of depredation by feral cats from photographs or videos now exists for endangered ‘Alae ‘Ula (Hawaiian Common Gallinule; Gallinula galeata ), Palila ( Loxioides bailleui ), ‘A‘o (Newell’s Shearwater; Puffinus newelli ), and ‘Ua‘u (Hawaiian Petrel; Pterodroma sandwichensis ) on multiple islands [28],[29],[30],[31]. The depredation of adults, documented in several cases, may be particularly detrimental to populations with life history attributes found in many Hawaiian bird species; delayed maturity, low reproductive potential, and extended nestling development[1].

Perhaps an even stronger and more compelling line of evidence for the effects of cats on bird populations comes from islands where cats have been removed. At least 33 bird populations, 22 of which were unique species, have increased, recolonized, or recovered following the removal of cats from 12 different islands or parts of islands throughout the world [30]. Thus, all predatory mammals are generally excluded, removed, or maintained at levels as low as possible before considering the reintroduction of endangered Hawaiian birds into the wild. For other endangered species living and migrating throughout larger landscapes, the task is more challenging. Ground-nesting birds such as Nēnē and seabirds can be protected in some breeding areas with fences that exclude predators, but they are still vulnerable during other periods of their life cycles. Options are more limited for forest-dwelling birds that nest high in trees such as those at Hakalau Forest NWR. Although there is arguably less risk from T. gondii infection for these species, depredation is nonetheless one of the major factors that additively contributes to the decline of native Hawaiian birds in the wild [1]. Not all limiting factors can be managed or mitigated but alleviating one or more key factors may play a large part of an effective strategy for the recovery of many endangered species. Enlarging predator-free areas or removing predators from entire islands, wherever possible, would provide refuges from not only from depredation, but also from the effects of T. gondii.
[1 ] Lindsey, G. D., S. C. Hess, E. W. Campbell III, and R. T. Sugihara. 2009. Small mammals as predators and competitors. Pp. 274–292 in Conservation biology of Hawaiian forest birds: Implications for island avifauna, T. Pratt, P. Banko, C. Atkinson J. Jacobi, and B. Woodworth, eds. Yale University Press, New Haven, Connecticut.
[2] Frenkel, J. K., J. P. Dubey, and N. L. Miller. 1970. Toxoplasma gondii in cats: fecal stages identified as coccidian oocysts. Science 167: 893–896.
[3] Wallace, G. D., L. Marshall, and M. Marshall. 1972. Cats, rats, and toxoplasmosis on a small Pacific island. American Journal of Epidemiology 95: 475–482.
[4] Dubey, J. P., and C. P. Beattie. 1998. Toxoplasmosis of animals and man. CRC Press, Boca Raton, FL.
[5] Dubey, J. P., M. R. Lappin, O. C. H. Kwok, S. Mofya, A. Chikweto, A. Baffa, D. Doherty, J. Shakeri, C. N. L. Macpherson, and R. N. Sharma. 2009 . Seroprevalence of Toxoplasma gondii and concurrent Bartonella spp., feline immunodeficiency virus, and feline leukemia virus infections in cats from Grenada, West Indies. Journal of Parasitology 95: 1129–1133.
[6] Danner, R. M, D. M. Goltz, S. C. Hess, and P. C. Banko. 2007. Evidence of feline immunodeficiency virus, feline leukemia virus, and Toxoplasma gondii in feral cats on Mauna Kea, Hawaii. Journal of Wildlife Diseases 43: 315–318.
[7] USGS unpubl. data.
[8] Verma, S. K., C. Su, and J. P. Dubey. Toxoplasma gondii isolates from mouflon sheep ( Ovis ammon ) from Hawaii, USA. Journal of Eukaryotic Microbiology 62:141–143.
[10] Dubey, J. P., and J. K. Frenkel. 1998. Toxoplasmosis of rats: a review, with considerations of their value as an animal model and their possible role in epidemiology. Veterinary parasitology 77: 1–32.
[11] Vyas, A., S.-K. Kim, N. Giacomini, J. C. Boothroyd, and R. M. Sapolsky. 2007. Behavioral changes induced by Toxoplasma infection of rodents are highly specific to aversion of cat odors. Proceedings of the National Academy of Sciences 104: 6442–6447.
[12] Dubey, J. P., and C. P. Beattie. 1998. Toxoplasmosis of animals and man. CRC Press, Boca Raton, FL.
[13] Jones, J. L., D. Kruszon-Moran, M. Wilson, G. McQuillan,T. Navin, and J. B. McAuley. 2001. Toxoplasma gondii infection in the United States: Seroprevalence and risk factors. American Journal of Epidemiology 154: 357–365.
[14] Work, T. M., J. G. Massey, B. A. Rideout, C. H. Gardiner, D. B. Ledig, O. C. H. Kwok, and J. P. Dubey. 2000. Fatal toxoplasmosis in free-ranging endangered ‘Alala from Hawaii. Journal of Wildlife Diseases 36: 205–212.
[15] Work, T. M., J. G. Massey, D. S. Lindsay, and J. P. Dubey. 2002. Toxoplasmosis in three species of native and introduced Hawaiian birds. Journal of Parasitology 88: 1040–1042.
[16] Work, T. M., J. Dagenais, R. Rameyer, and R. Breeden. 2015. Mortality patterns in endangered Hawaiian geese (Nene; Branta sanvicensis ). Journal of Wildlife Diseases 36: 205–212.
[17] Torrey, E. F., and R. H. Yolken. 2013. Toxoplasma oocysts as a public health problem. Trends in Parasitology 29: 380–384.
[18] Lindsay, D. S., M. V. Collins, S. M. Mitchell, R. A. Cole, G. J. Flick , C. N. Wetch, A. Lindquist, and J. P. Dubey. 2003. Sporulation and survival of Toxoplasma gondii ooysts in seawater. Journal of Eukaryotic Microbiology 50:687–688.
[19] Davis, A. A., C. A. Lepczyk, K. H. Haman, C. W. Morden, S. E. Crow, N. Jensen, and M. T. Lohr. 2018. Toxoplasma gondii detection in fecal samples from domestic cats ( Felis catus ) in Hawai‘i . Pacific Science 72: 501–511.
[20] Lass, A., H. Pietkiewicz, E. Modzelewska, A. Dumètre, B. Szostakowska, and P. Myjak. 2009. Detection of Toxoplasma gondii oocysts in environmental soil samples using molecular methods. European Journal of Clinical Microbiology 28: 599–605.
[21] Dabritz, H. A., M. A. Miller, E. R. Atwill, I. A. Gardner, C. M. Leutenegger, A. C. Melli, and P. A. Conrad. 2007. Detection of Toxoplasma gondii -like oocysts in cat feces and estimates of the environmental oocyst burden. Journal of the American Veterinary Medical Association 231: 1676–84.
[22] Holshuh, H. J., A. E. Sherrod, C. R. Taylor, B. F. Andrews, and E. B. Howard. 1985. Toxoplasmosis in a northern fur seal. Journal of the American Veterinary Medical Association 187: 1229–1230.
[23] Deem, S. L., J. Merkel, L. Ballweber, F. H. Vargas, M. B. Cruz, and P. G. Parker. 2010. Exposure to Toxoplasma gondii in Galapagos Penguins ( Spheniscus mendiculus ) and flightless cormorants ( Phalacrocorax harrisi ) in the Galapagos Islands, Ecuador. Journal of Wildlife Diseases 46: 1005–1011.
[24] Migaki, G., T. R. Sawa, and J. P. Dubey. 1990. Fatal Disseminated Toxoplasmosis in a Spinner Dolphin ( Stenella longirostris ). Veterinary Pathology 27:463–464.
[25] Conrad P.A., M.A.Miller, C.Kreuder, E.R. James, I.Mazet, H. Dabritz, D.A. Jessup, F. Gulland, and M.E.
Grigg.2005 Transmission of toxoplasma: clues from the study of sea otters as sentinels of Toxoplasma gondii flow into the marine environment. International Journal for Parasitology 35: 1155-1168
[26] M. Barbieri, NOAA, pers. comm.
[27] Honnold, S. P., R. Braun, D. P. Scott, C. Sreekumar, and J. P. Dubey. 2005. Toxoplasmosis in a Hawaiian monk seal ( Monachus schauinslandi ). Journal of Parasitology 91: 695–697.
[28] K. Uyehara, USFWS, pers. comm.
[29] A. Raine, Kaua‘i Endangered Seabird Recovery Project, pers. comm.
[30] Hess, S. C. 2014. Strength of evidence for the effects of feral cats on insular wildlife: The club med syndrome part II. Proceedings of the Vertebrate Pest Conference 26: 211–216.
[31] Judge, S., J. S. Lippert, K. Misajon, D. Hu, and S. C. Hess. 2012. Videographic evidence of endangered species depredation by feral cat. Pacific Conservation Biology 18: 293–296.

Friends of Hakalau Forest, National Wildlife Refuge is a 501 ( C ) ( 3 ) organization and is recognized as a tax exempt non-profit organization by the Federal government and the State of Hawaii. We appreciate and thank you for your membership and your donations.