Seasonality and prevalence of pollen collected from Hawaiian nectarivorous birds

By Kathryn N. van Dyk, Kristina L. Paxton, Patrick J. Hart, and Eben H. Paxton*

Abstract Hawaiian nectarivorous forest birds play a vital ecological role as pollinators in Hawaiian ecosystems. However, little is known about what nectar resources are utilized by ’s nectarivorous birds, how seasonality influences nectar availability, and how nectar preference differs by bird species. We sampled pollen from the heads of ‘i‘iwi (Drepanis coccinea), ‘apapane (Himatione sanguinea), Hawai‘i ‘amakihi (Chlorodrepanis virens), and the non-native Japanese white-eye (Zosterops japonicas) captured at Hakalau Forest National Wildlife Refuge on Hawai‘i Island. ‘Ōhi‘a (Metrosideros polymorpha) was the most prevalent pollen species, observed throughout the sampling period while other pollen species were more seasonal in occurrence. Consistent with the peak flowering phenology of the species, pollen from koa (Acacia koa), māmane (Sophora chrysophylla), and gorse (Ulex europaeus) plant species were more commonly sampled from birds in the winter months, while ‘ōhelo (Vaccinium reticulatum), ‘ākala ( hawaiensis), and () were more prevalent during the spring months. We also found an association between bird species and pollen resources, with ‘i‘iwi and Hawai‘i ‘amakihi having a higher diversity of pollen than ‘apapane and Japanese white-eye, which primarily had just ‘ōhi‘a. These results demonstrate that ‘ōhi‘a is likely the most important nectar resource for Hawai‘i’s nectar feeding birds, but seasonally abundant nectar may be important for some species.

*Corresponding Author E-mail: [email protected]

Pacific Science, vol. 73, no. 2 December 5, 2018 (Early view) Introduction

In flowering , flower shape, color, and structure have evolved to attract animals to nectar resources for the purpose of enhancing biotic pollination, resulting in animal species that have become dependent on nectar for survival (Opler 1983). This evolution has created a codependence between flowering plants and nectarivores. Flowering plants benefit from this mutualistic relationship through enhanced gene flow and reproductive success, and in turn, nectar provides a food resource rich in sugar and energy to many animals (Nicolson and Fleming 2003). Insects are responsible for the majority of the world’s pollination (Proctor et al. 1996). However, some vertebrate species, primarily birds and bats, serve important ecological roles as pollinators (Sekercioglu 2006). More than 900 species of birds, including sunbirds, hummingbirds, honeyeaters, and honeycreepers, pollinate approximately 500 species of plants

(Nebhan and Buchmann 1997). Birds are amongst the most effective pollinators, as birds have high-energy demands requiring more frequent visits to flowers than insects (Schuchmann 1999). Moreover, birds travel further distances than most insects while foraging and are more likely to pollinate rare plants and species that are widely dispersed across large distances (Cox and Elmqvist 2000). Avian pollination is particularly important in island ecosystems where there are often fewer pollinator species and some plant species are unable to self-pollinate (Cox and Elmqvist 2000).

In Hawai‘i, bird pollination serves a critical ecological role as many and bird species have coevolved with one another (Sakai et al. 2002, Price and Wagner 2004). Currently, there are three native bird species whose primary food resource is nectar, and an additional three generalists that frequently feed on nectar. But since the arrival of Polynesians and more recently Europeans, 52 species of native Hawaiian birds have gone extinct because of impacts from habitat loss, introduced plant and animal species, and non-native disease, and 57% percent of the remaining species are endangered or threatened (Paxton et al. 2018). Insect pollinators also play an important role in pollination (Magnacca

2007), and at least 52 species of endemic bees and 26 species of endemic moths have been lost in Hawai‘i

(Stein et al. 2000). The ecological consequences of the extinction of these pollinators may have been large and threatens Hawai‘i’s plant species and ecosystems (Aslan et al. 2013). For example, the endemic plant ie’ie (Freycinetia arborea) depends on bird pollination, and detection of ie’ie pollen grains on museum specimens from now critically endangered or extinct forest birds indicate the loss of potentially important pollinators (Cox 1983). However, the non-native Japanese white-eye (Zosterops japonicas) has been observed feeding on ʻieʻie bracts, and may presently be an important pollinator for the vine (Cox

1983). The white-eye has been shown to be an effective pollinator for some native Hawaiian plants, but not others (Aslan et al. 2014), indicating the limited potential of novel species to fill the gap in plant- animal pollination services. Cox and Elmqvist (2000) estimated 31 species in the Campanulaceae family have gone extinct in part because of the loss of native Hawaiian nectarivorous birds and other insect pollinators, and other species may be experiencing reduced fitness with reduced pollination (Ghazoul

2005). Therefore, understanding the ecological role of Hawai‘i’s remaining birds as pollinators for both the conservation of Hawaiian birds and plants remains a critical issue.

Most of what is known about forage selection of Hawai‘i’s nectarivorous birds is based on observational data (Richards and Bock 1973, Warning et al. 1993). However, observational studies can miss pollination of rare plants given the short window of time birds are observed, and often cannot estimate the relative importance of different flowers as birds move through the forest over time. Past observational studies indicate that ʻōhiʻa (Metrosideros polymorpha) is the primary nectar resource utilized by Hawai‘i’s native nectarivorous birds, with limited observations of birds feeding on other plant species (Richards and Block 1973, Warning et al. 1993). For example, Hawai‘i ‘amakihi (Chlorodrepanis virens) has been observed foraging on the nectar of māmane (Sophora chrysophylla) and native lobelias

(Campanulaceae sp.), and several species of Hawaiian birds are also known to feed on invasive species, including the Cytisus palmensis and Lantana sp. (Richards and Bock 1973). To quantify important plant species to Hawai‘i’s nectarivorous birds, we studied pollen samples collected from nectarivorous forest birds on the windward side of Hawai‘i Island. We evaluated how the presence of pollen on birds varied as a function of bird species and season. The blooming phenology of plants varies across the period of time sampled, and we predicted there would be a strong seasonal pattern in the occurrence of pollen found on bird species. The bird species ranged from nectarivorous specialists to generalists, and we expected to see a higher diversity of pollen species in the primarily nectarivorous species. Methods

Data for this project were collected at Hakalau Forest National Wildlife Refuge (Hakalau).

Hakalau was established in 1985 for the purpose of protecting native Hawaiian bird species and the forest habitats they depend on, and preserves 13,247 ha on the eastern slope of Mauna Kea, Hawai‘i Island, at elevations ranging from 600 - 1,800 meters (USFWS 2010). Extensive restoration of pasture lands in the upper elevation area of the refuge has increased the extent and diversity of the forest, which has been rapidly colonized by birds from the adjacent intact forest (Paxton et al. 2017). The canopy is dominated by native ‘ōhiʻa and koa (Acacia koa) trees, while the mid-story canopy has a rich diversity of native species including kanawao (Broussaisia arguta), ‘olapa (Cheirodendron trigynum), maile (Alixia oliviformis), pilo (Coprosma ochracea), pūkiawe (Leptecophylla tameiameiae), kāwa‘u (Ilex anomala), kōlea (Myrsine lessertiana), ‘ōhelo (Vaccinium calycinum), ‘ākala () and hapu‘u

(Cibotium glaucum) (Cole and Litten 2014). Common non-native species at Hakalau include various grass species, gorse (Ulex europaeus), blackberry (Rubus argutus), banana poka (Passiflora tarminiana), and holly (Ilex aquifolium) (USFWS 2010).

Common bird species at our study site include Hawai‘i ‘amakihi, ‘i‘iwi (Drepanis coccinea),

‘apapane (Himatione sanguinea), Hawai‘i ‘elepaio (Chasiempis sandwichensis), ‘ōma‘o (Myadestes obscurus), and the non-native Japanese white-eye and red-billed leiothrix (Leiothrix lutea) (Camp et al.

2015). Of these species, the ‘i‘iwi and ‘apapane are primarily nectarivorous species, and have been documented moving long distances in search of nectar (Carpenter and MacMillen 1975, Guillaumet et al.

2017). The Hawai‘i ‘amakihi and Japanese white-eye are generalists that will readily forage for nectar, while the ‘ōma‘o and red-billed leiothrix are primarily frugivorous, and the Hawai‘i ‘elapaio is an insectivore.

As part of a bird demographic study conducted at Hakalau, we sampled pollen on birds captured from November 2015 to May 2016. Birds were sampled from three locations within the upper elevation portions of the refuge, representing sites from intact ‘ōhiʻa/koa dominated canopies to recently restored forests dominated by koa. We obtained pollen samples by gently pressing crystal clear scotch tape to the birds’ foreheads, around the top of the bill, and to each side of the bill. Although the collection method was standardized, we believe there is enough variation among samples that we limited our analysis to the occurrence of distinct pollen species and not counts of individual pollen grains. The average size of each piece of tape was approximately 38mm by 19mm. We then placed the tape on a standard microscope slide measuring 25mm by 76mm and 1 mm thick for storage and subsequent analysis. We restricted our analysis to ‘i‘iwi, ‘apapane, Hawai‘i ‘amakihi, and Japanese white-eye because these four species consistently had pollen on the samples collected.

A reference library was created of pollen samples from the most common plant species present at

Hakalau. Crystal clear scotch tape was pressed to flowers to collect pollen and applied to a microscope slide as described above. Pictures from a camera attached to the microscope were taken of these pollen samples, and these pictures were used to help identify pollen species found on the bird pollen samples.

Pollen samples collected from the birds at Hakalau were analyzed using an Olympus BX51 microscope with the 20X lens. Each microscope slide was scanned with ten straight passes along the entire length of tape under the microscope. These ten sweeps were equally divided along the slide by eye.

The observed pollen species were recorded as presence or absence, and unknown species were photographed and measured. For ‘ōhi‘a, the most prevalent species, pollen quantity was categorized as none, small (1-100 grains), medium, (101-1,000 grains), or large (> 1,000 grains). The amount of time spent on each scan varied by how much pollen was observed, but took an average of two minutes, for an average of 20 minutes scanning time per slide.

R We calculated the Shannon’s diversity index ( H||'=∑ pi ln pi)for each bird species to compare i=1 the diversity of the pollen species among birds, with higher values representing greater diversity. For each bird species, we summed the number of slides that contained at least 1 grain of a pollen species (i) out of all pollen species for a given bird (R) to calculate the proportion of pollen species sampled per bird (pi).

To be consistent with the other analyses, we only included known pollen samples for the diversity index estimates. We also evaluated the similarity of total pollen species composition across bird species by calculating a Sorensen’s Coefficient for each pairwise comparison of bird species. Calculated values from this equation range from 0-1, with values closer to 1 indicating similar species composition of pollen between two bird species and values closer to 0 indicating dissimilar species composition. We tested for non-independent associations between pollen species and bird species, and changes in pollen frequency by season, using a chi-square test in Program R (3.3.2, R Core Team) with a Monte Carlo simulation of

10,000 replicates to estimate p-values, which corrects for small sample sizes within some categories.

Results

We analyzed samples from 193 birds captured at Hakalau from November 2015 to May 2016

(Table 1). Samples included 30 ‘apapane, 63 Hawai‘i ‘amakihi, 68 ‘i‘iwi, and 32 Japanese white-eyes. On average, 3.5 (0-8) pollen species were detected per bird. ‘Ōhi‘a was the most prevalent pollen species, found in 98% of all pollen samples (Fig. 1A), and approximately half the samples had medium to large quantities of ‘ōhi‘a pollen (Fig. 1B). Other important plants included koa (21% of samples), ‘ōhelo

(12%), blackberry (10%), pūkiawe (8%), māmane (7%), ‘ākala (7%), and gorse (5%)(Table 1, Fig. 1B).

Less frequent observations included naio (Myoporum sandwicense), kanawao, strawberry guava (Psidium cattleianum), honey suckle (Lonicera sp.), ginger spp., and kāwa‘u. In addition, pollen from 37 distinct but unidentified plant species was observed, most occurring at very low frequencies.

We found a non-random association between bird species and plant species pollen (X2 = 47.11, P

< 0.001) (Fig. 1B), suggesting bird species flower visitation rates are non-random. For example, we found more koa pollen on ‘apapane than expected, whether for nectar or to forage for arthropods among the flowers, but lower counts of pollen for the other common plant species. Considering the breadth of known plant pollen species found on ‘apapane, its Shannon’s diversity index was calculated at 1.53. In contrast,

‘i‘iwi had a more diverse range of plant species, feeding on ‘ōhi‘a, koa, ‘ōhelo, and māmane, resulting in a higher Shannon’s diversity index of 1.79. The generalist Hawai‘i ‘amakihi had a high diversity of pollen detected, particularly ‘ōhi‘a, koa, and ‘ōhelo, with a Shannon’s diversity index of 1.72. However, the other generalist, the Japanese white-eye, had pollen primarily from ‘ōhi‘a with only a few samples containing ‘ōhelo, and a low Shannon’s diversity index of 1.66. Despite differences in the prevalence of pollen species across bird species, overall pollen species composition did not vary much among bird species, with Sorenson’s Coefficients ranging from 0.80-0.91 indicating high overlap in pollen species among the bird species sampled.

We detected strong seasonal patterns in the occurrence of the eight most common pollen species sampled from birds at Hakalau across the seven-month period, grouped within three time periods;

December-January, February-March, and April-May (X2 = 47.11, P < 0.001)(Fig. 2). Some pollen species were more prevalent in the samples collected from birds during the winter months (December – March), including koa, māmane, and gorse, while other pollen species, such as ‘ōhelo, ‘ākala, and blackberry, were more prevalent in samples collected during the spring months (April – May).

Discussion

Although Hakalau supports a diverse plant community, and pollen from a number of plant species were detected, pollen from ‘ōhi‘a trees was the dominant pollen grain detected for all forest birds sampled in this study across the seven-month period. Overall, ‘ōhi‘a pollen was detected on 98% of samples, often in high numbers. Many slides were entirely coated with ‘ōhi‘a pollen and observing and identifying other pollen species was analogous to looking for a needle in a haystack. ‘Ōhi‘a is the dominant tree species at

Hakalau (USFWS 2010), as well as throughout Hawai‘i, and while the abundance of ‘ōhi‘a flowers varies seasonally, flowers are present year-round (Carpenter 1976). In contrast, other plant species at Hakalau only flower for specific periods, and we found high seasonality in the presence of other pollen species detected on birds. For example, koa, māmane, and gorse were more prevalent in bird pollen samples in the winter, and ‘ōhelo, ‘ākala, and blackberry were more common in the spring, which matches the flowering phenology of the plants within the study area.

Historically, long-distance flights by large flocks of ‘apapane and ‘i‘iwi have been documented on Hawai‘i Island (MacMillen and Carpenter 1980, Ralph and Fancy 1995), suggesting movement between areas with abundant flower bloom and night roosts. While koa, ‘ōhelo, ‘ākala, and blackberry are common within the refuge boundaries, māmane and gorse are less common, largely occurring in the uppermost reaches of the refuge, but occur in high densities outside the refuge boundaries above Hakalau up into the subalpine forests on Mauna Kea (Hess et al. 2001). Seasonally, māmane produces abundant flowers, and researchers in the early 1990’s documented significant increases in ‘apapane and ‘i‘iwi corresponding with peak māmane bloom, which were believed to be birds from lower elevation forests seasonally migrating to the higher subalpine forests to capitalize on abundant māmane nectar (Hess et al.

2001). However, more recent analysis of forest bird occurrence in subalpine forests of Mauna Kea indicate a decline in seasonal visitation by ‘apapane and ‘i‘iwi compared to historic rates, which may be indicative of declining bird populations (Banko et al. 2013). Our results suggest that at least ‘i‘iwi may still be making elevation movements, albeit in lower numbers, and māmane in sub-alpine forests may still be an important nectar resource for the birds at Hakalau in the winter during the peak māmane flowering period. Concurrent with increased māmane pollen in the winter months is a similar seasonal increase in gorse pollen. Gorse is an invasive that is abundant in the region between Hakalau’s wet and mesic forests and the subalpine māmane forests on Mauna Kea, and the presence of gorse concurrent with māmane pollen is consistent with the hypothesis that birds are making altitudinal migrations to māmane forests, and transiting through large patches of gorse. However, given the apparent lack of nectar in gorse flowers (Zouhar 2005), birds are most likely foraging on abundant insect visitors to flowers during visits to gorse.

All four bird species sampled occupy the same forest habitat, but we detected differences in the diversity of pollen species. ‘Apapane had the lowest pollen species diversity, with a high representation of

‘ōhi‘a pollen. Additionally, koa pollen was detected at a higher prevalence for ‘apapane than in other species, suggesting that ‘apapane may forage at low levels on other plant species such as koa for either nectar or insects. Japanese white-eyes also had a low diversity of pollen species detected, but ‘ōhelo and pūkiawe may be important plant species for these birds in certain months. White-eye movements and densities have been strongly linked to the availability of ‘ōhi‘a blossoms (Hart et al. 2011), which is consistent with the dominance of ‘ōhi‘a pollen in white-eye samples. Both ‘apapane and Japanese white- eyes have the smallest sample size, and larger sample sizes might result in greater diversity. However,

‘apapane largely stay in the upper canopies of the forest (Ralph and Fancy 1995), and the tree canopy at

Hakalau is dominated by ‘ōhi‘a and koa, which are the dominant pollen species on ‘apapane. Japanese white-eyes have been documented nectar robbing in Hawai‘i (taking the nectar from plants without coming into contact with its reproductive structures and participating in pollination; Gardener and

Daehler 2006), as well as other species of forest birds found in Hakalau, which could lead to an underrepresentation of nectar via examination of pollen found on birds. On the other hand, birds foraging for arthropods in and around flowers may pick up pollen when they are not pursuing nectar, which could over represent nectar use estimates from the presence of pollen. Therefore, care is needed in interpreting the presence or absence of pollen due to its potentially imperfect measure of the actual selection of nectar resources. For example, ‘i‘iwi are frequently found foraging on nectar from the flowers of banana poka, an invasive vine found in parts of the refuge, but they access the nectar by making a small hole at the base of the flower and may never come in contact with the pollen.

‘I‘iwi had the highest pollen species diversity of the four species studied. ‘I‘iwi, with its long decurved bill, is believed to have co-evolved with the many native Hawaiian plants that had long, decurved flower corollas (Smith et al. 1995). While many of these plants are extinct or very rare, ‘i‘iwi are frequently detected below the forest canopy when understory shrubs such as ‘ākala are in bloom, and foraging in the understory would provide greater access to a diversity of flowering plants. In addition,

‘i‘iwi make altitudinal migrations seasonally in search of nectar (Guillaumet et al. 2017), and such long- distance movements may expose ‘i‘iwi to a higher diversity of flower plants, although all the identified pollen species were common in the main study area. We also observed a high diversity of pollen species for Hawai‘i ‘amakihi, a generalist feeder (i.e., insects, nectar, and some ; Baldwin 1953). Given the lack of specialization on nectar, we had predicted Hawai‘i ‘amakihi would have lower pollen diversity compared to ‘i‘iwi and ‘apapane. However, ‘amakihi frequently forage in the understory of forest habitats, and therefore may have a high encounter rate with flowering plants, or may incidentally brush against flowers as they forage for arthropods. Hawai‘i ‘amakihi are believed to be less likely to travel long distances to forage compared to ‘apapane and ‘i‘iwi (Hart et al. 2011), and Hawai‘i ‘amakihi may compensate for this lack of movement by feeding on insects and a greater diversity of nectar resources.

The potential importance of Hawai‘i’s nectarivorous birds as pollinators is evident for several species of Hawaiian plants, particularly ‘ōhi‘a, koa, māmane, ‘ōhelo, ‘ākala, and pūkiawe, and perhaps other rare species that we were unable to identify. As Hawai‘i has lost many of its endemic pollinators (Stein et al. 2000, Banko and Banko 2009), it is increasingly important to protect and preserve the remaining bird species so that they can continue to fulfill their ecological roles as pollinators in Hawaiian ecosystems. Native insect pollinators, such as Hylaeus bees, can provide important pollination functions as well, but they tend to specialize on specific plant species and are limited in their dispersal distances

(Miller et al 2015). The more generalist diet of the birds, as suggested by our results, means that both beneficial and non-beneficial pollination may be occurring. Five of the 14 plant species identified from pollen were non-native species, indicating that forest birds may be playing a role in the establishment and spread of invasive species. However, pollen from native plant species was dominant, and removal of invasive plant species will be beneficial to forest regeneration and health which will ultimately be more beneficial to forest birds in the long run.

This study provides a first look at likely sources of nectar for Hawai‘i’s forest birds, and the role that birds may play in pollination. While the prevalence of pollen on birds may not reflect their complete diet, the presence of pollen on birds indicates their potential for pollination. However, more work is needed to understand yearly variation in bird diet, and document pollen found on birds at additional sites.

It is also important to note that some components of a bird’s diet may not be represented by the prevalence of pollen samples on birds given that 1) birds can forage for arthropods near flowers and incidentally pick up pollen, 2) nectar rob, or 3) differences in either flower morphology or stickiness of pollen may result in some plants being better at attaching pollen to birds. In addition, our study did not document Hawaiian birds pollinating rare species, although incidental observations in Hakalau indicate that outplanted endangered plants are visited by forest birds. Thus multiple years of sampling large numbers of birds may be required to fully describe variation in the use of common plants and the incidence of rare plants. We found the tape collection method to be simple and quick, and extremely effective in quickly identifying pollen species present on birds. However, pollen from some species, such as māmane and ‘ākala, look very similar, and misidentifications may explain why we have some observations of ‘ākala, a species that typically blooms in spring, observed during the winter. Advances in molecular genetic technology, such as DNA barcoding (Bell et al. 2016), may allow for better identification and quantification of pollen species and complement microscope methods. Birds are known to be valuable for rare plant pollination due to their high-energy demands and flight capabilities (Cox and

Elmqvist 2000), and thus it is important to further understand Hawaiian bird’s contribution to rare plant pollination.

Avian pollinators face threats of disease and habitat loss, such as the recently identified

Ceratocystis fungus that causes Rapid ‘Ōhi‘a Death and had infected 75,000 acres of ‘ōhi‘a forest as of

2017 (Keith et al. 2015). Although no nectarivore was completely dependent on ‘ōhi‘a, our study highlights the importance of ‘ōhi‘a nectar for Hawai‘i’s nectarivorous bird species throughout the study period. Therefore, Rapid ‘Ōhi‘a Death has the potential to devastate the foraging resources of Hawai‘i’s nectar-feeding birds in areas where ‘ōhi‘a mortality is high. Concerns about potential large-scale habitat loss, as well as the threat of avian diseases, led to the listing of ‘i‘iwi as a Threatened Species (USFWS

2017), highlighting that the threats to Hawai‘i’s nectarivorous birds persist and need to be addressed. The dependence of both birds on forest habitats, and native forest communities on birds for pollination and seed dispersal, highlights the importance of understanding ecological relationships across trophic levels to better understand and manage Hawaiian forest ecosystems.

Acknowledgements

Funding for the banding work was provided by the U.S. Geological Survey Science Support grants and the U.S. Fish and Wildlife Inventory and Monitoring. Funding to help with analysis of the pollen came from the Hawai‘i Audubon Society. We thank the USGS banding crew and University of Hawai‘i at Hilo

Listening Observatory for Hawaiian Ecosystems (LOHE) lab for help in collecting samples, and Cari

Lynn Squibb for help in processing pollen samples. We appreciate the support and land access permission provided by Hakalau Forest National Wildlife Refuge. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

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Zouhar, K. 2005. Ulex europaeus. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory. Available: https://www.fs.fed.us/database/feis/plants/shrub/uleeur/all.html [2018, October 14]. Figure 1. Frequencies of the eight most common pollen plant species collected from nectarivorous forest birds sampled at Hakalau Forest National Wildlife Refuge, Hawai‘i. Panel A indicates the quantity of

‘ōhi‘a pollen grains detected in each sample. Panel B indicates the proportion of slides that had at least one pollen grain from each plant species separated by bird species. Non-native plant species are indicated by an asterisk. Figure 2. Frequencies of pollen occurrences on nectarivorous forest bird species at Hakalau Forest

National Wildlife refuge, Hawai‘i, for the seven most common pollen plant species in the months of

December to May. ‘Ōhi‘a is excluded from this figure because of its high and constant frequency throughout the study period. Non-native plant species are indicated by an asterisk. Table 1: Number of samples detected with plant species’ pollen per nectarivorous forest bird species, by season. Each number indicates a sample

with at least 1 pollen grain detected for the given plant species. Non-native plant species are indicated by an asterisk.

‘ōhel blackberry pūkiaw ‘ākal māman gorse nai guava honeysuckle ginger kanawa kāwa‘ Unidentifie Species Season n ‘ōhiʻa koa o * e a e * o * * * o u d ‘apapan e Dec_Jan 4 4 3 0 0 0 0 0 0 0 0 0 0 0 0 1 2 Feb_Mar 2 22 7 2 2 2 1 1 1 1 1 0 0 1 0 15 Apr_Ma y 4 4 0 0 0 0 0 0 0 0 0 0 0 0 0 4 1 Dec_Jan 4 14 7 0 0 0 0 0 1 0 0 0 0 0 0 7 Hawai‘i 3 ‘amakihi Feb_Mar 5 31 8 6 2 3 2 2 2 0 1 1 0 0 1 28 Apr_Ma 1 y 4 14 1 2 3 2 2 0 0 0 0 0 0 0 0 14 3 ‘i‘iwi Dec_Jan 6 36 7 2 1 1 2 4 2 0 1 0 1 0 0 20 2 Feb_Mar 0 20 6 3 5 3 3 3 1 2 0 1 0 0 0 13 Apr_Ma 1 y 2 12 0 1 3 0 1 1 1 0 0 0 1 0 0 9 Dec_Jan 3 3 0 0 0 0 0 0 0 0 0 0 0 0 0 1 Japanese 1 white- Feb_Mar 2 12 0 2 0 4 0 0 0 0 0 0 0 0 0 8 eye Apr_Ma 1 y 7 17 1 5 3 0 3 1 1 1 0 0 0 0 0 15