A naturalist in Hawai’i

Sandy beaches, warm water, exotic life and lots of sun! That is the picture we have of Hawaii. And it has all of that, but there is another side to the islands, particularly O’ahu, which is where the capital Honolulu is situated, including world famous Waikiki Beach. My first time there was with my wife as newlyweds on our honeymoon in early January 1986. This time we traveled there at the end of January with our two sons and their respective partners. It was an opportunity to have a week together as a family, and it was everything we had hoped it would be in terms of a family holiday. In this blog I will describe some of my impressions of O’ahu, including some of the changes that have occurred in the 32 years since my first visit, but mostly focusing on animal life.


View of Waikiki from Diamond Head with Kapiʻolani Park in the foreground.

My impression of Honolulu was that it was much busier than 32 years ago. Looking at some population statistics it would appear that the population has grown, but not by that much. It is likely that the change is largely due to tourism, and it is indeed impossible to find a place where you are more or less on your own. The closest spots we found were at the Harold L. Lyon Arboretum, a 200 acre garden in the Mānoa Valley, and the Ka’ena Point State Park (and neither of those were exactly deserted!) Everywhere else tourists were not in short supply. As a result, traffic was generally heavy, particularly around Honolulu, and at some of the attractions it was more or less impossible to find parking, e.g., Hanauma Bay and Waimea Falls. The latter we missed altogether because of absolute mayhem due to the Volcom Pipe Pro 2018 surfing festival.

Driving around the island the incredible gap between rich and poor was striking. Along the highways were numerous vandalized vehicles (including a Mazda Tribute that had been pushed over a cliff along the southern access trail to Ka‘ena Point. In addition, many beach parks had vast tent cities, often displaying the Kanaka Maoli flag. It turns out that Hawai’i has a huge homeless problem (we drove by the huge tent city in Waianae, described in that article), in part because of a migrant crisis. So while tourism is thriving, largely driving the Island State‘s economy and no doubt making some people very wealthy, the native Hawai’ian people are often marginalized. What was once their paradise, is now overrun by tourists and those who profit from us sun-seekers. Waikiki is kept pristine, but outlying areas often have a component of poverty which is hard to reconcile with the affluence of the privileged.

There is also an ongoing and (apparently) deepening ecological crisis. Small Indian mongoose (Herpestes javanicus) is now established and widespread on O’ahu and most

Hanauma Bay-0040 Mongooses

Two mongooses at Hanauma Bay, which was also heavily populated by feral cats.

other Hawai’ian Islands (except Lanaʻi and Kauaʻi, but see this article). They were introduced in a poorly thought out attempt to control rodent populations in sugar cane, resulting in dramatic impacts on native Hawai’ian fauna. We literally saw mongoose wherever we went.  The mongoose is about the size of a ferret, but its body posture is interestingly stiff, making it almost look like a large, running stick as they duck in and out of the vegetation. Leaving any food unattended will draw them in very quickly. Another mammal species of concern is the feral pig (Sus scrofa), both because of destructive habits to plants, digging which causes erosion,  as well as making wallows where mosquitoes (also exotic to the islands) can breed. Pigs were originally introduced by Polynesian settlers, and later by Europeans. We did not see any, but in Manoa Valley we saw a notice about feral pig hunting.

What really struck me as most disturbing were perhaps the feral cats, however. In places they were as numerous as the feral rabbits at Vancouver Island University, if you have ever witnessed that (I know that University of Victoria had a similar problem, but I am unaware of the current status). Most people are aware that feral cats (and domestic allowed to roam outdoors) can have devastating impacts on bird populations. In Hawai’i that is a serious problem since many of the indigenous bird species, most of which are threatened or endangered, have few or no evolved defenses against mammal predators. But that is not the only problem. Another serious threat is the potential for the protozoan parasite Toxoplasma gondii to spread to susceptible animals, including the Hawaiian monk seal (Neomonachus schauinslandi). Several of these endangered seals have died from toxoplasmosis. The parasite depends on cats for reproduction, and the huge number of cats ensure that it is in Hawai’i to stay. As is the case everywhere with feral “pet” animals, powerful animal rights lobbies make management of this situation very difficult. Trap, neuter and release tactics have been used, but with a population of cats on O’ahu alone perhaps pushing half a million cats, plus a potentially long life of cats in a benign environment, the impact would be fairly minimal.  (The link above takes you to a long article, but it explains the situation quite well).

Amphibians and reptiles have also been introduced, either deliberately or accidentally (=pets released or escaped). The most common reptile was the brown anole (Anolis sagrei), which is plentiful in suburban areas. Geckos are also present. At night you could hear house geckos (Hemidactylus frenatus) chirping, although we never saw one. Several other gecko species also occur, as do at least two species of chameleon (neither of which we saw). In addition, bull frogs (Lithobates catesbianus) and the infamous cane toad (Rhinella  marina) have been introduced as biocontrol agents.  We spotted a cane toad

Manoa Falls-8755

A cane toad hiding in a pond at the Harold L. Lyon Arboretum in Manoa Valley, Oahu, HI.

and a wrinkled frog (Rana rugosa) sharing a pond at the Lyon arboretum, and a dead poison arrow frog (Dendrobates auratus) along the Manoa Falls trail. Other amphibians are listed here, including the coqui frog (Eleutherodactylus coqui), which keeps people awake with its loud call.

A surprise to me was the huge numbers of cichlids occupying lagoons and rivers.

Cichlids in Ala Wai Canal, Waikiki

Cichlids in Ala Wai Canal, Waikiki, O’ahu, HI

Invasive aquatics are of course not as obvious as terrestrial organisms, but the cichlids were front and center, e.g., in the Ala Wai Canal at Waikiki. A quick check on the web shows that numerous “aquarium” fish are present. We also saw guppy (Poecilia reticulata), mosquitofish (Gambusia affinis), and sailfin molly (Poecilia latipinna) in various ponds. Some of these were presumably introduced for mosquito control.

We spent some time birding, which is fun even though the vast majority of species you see is non-native. Red jungle fowl (Gallus gallus)  can be found just about everywhere, with roosters driving people mad.  I don‘t recall seeing any in 1986, but apparently this species is thought to have arrived with Polynesian settlers as much as 1300-1500 years ago. The original taxon probably disappeared on most islands with the introduction of predators, and although reintroductions of true jungle fowl have been attempted, the current population is largely mixed with domestic chicken. A recent paper showed that Red jungle fowl genes from the original introduction still exist on Kauaʻi (Gering et al. 2015). The rest can probably be characterized as “cage birds”, i.e., they are the kind of birds that people have as pets in cages. That includes several species of parrot, which can be quite destructive.  We saw 32 bird species, of which only a handful were native, and none endemic.

I neglected the insects, pretty much, but one prominent insect could not be missed, and again it was a surprise to me. It was in fact the monarch butterfly (Danaus plexippus),

Haleiwa-8994 Monarch

Monarch butterfly in Haleʻiwa, O’ahu, HI

which was seen almost everywhere we went.

In summary, O’ahu is really a poster child for how human manipulation of fauna and flora impacts a sensitive ecosystem. Enormous efforts are being made to conserve the remnants of native Hawaiian fauna and flora, but given the enormous pressures from human populations, it may be too late for most. There have been some success stories, however, so all may not be lost! O’ahu still offers plenty for the tourist, but if I went to Hawai’i specifically for a nature experience, I would probably pick one of the less populated islands.


Gering, E, Johnsson, M, Willis, P, Getty, T, and Wright, D (2015) Mixed ancestry and admixture in Kauai’s feral chickens: invasion of domestic genes into ancient Red Junglefowl reservoirs. Mol. Ecol. 24: 2112-24. doi: 10.1111/mec.13096.

Postscript: This post from BBC describes the evolutionary history of the Hawaiian Islands, discussing what we have lost and what we stand to lose if the remaining endemic species cannot be saved..


About cinnabarreflections

B. Staffan Lindgren is Professor Emeritus at UNBC. Living in Nanaimo, BC. Jack of all trades trying to stay relevant.
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2 Responses to A naturalist in Hawai’i

  1. Pingback: A naturalist in Hawaii Part III: Attack by the aliens | Cinnabar Reflections

  2. Pingback: Life in space – An earthling biologist’s perspective. | Cinnabar Reflections

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