Kaelepulu Wetland - Home to Endangered Hawaiian Wetland Birds

Late Summer Report for Ka’elepulu Wetland, 6-26-05 to 9-3-05

Introduction

During July and August breeding activity for most native birds stopped. There was a two broods of coots and 2 broods of gallinules hatched on the week of 7-10 . The mallards hatched several broods during the report period.

A typical hot dry weather pattern developed in July and persisted through August. There were light morning showers occasionally. The water level was typically low in the lake. Rat baiting and bullfrog trapping was done continuously.

Vegetation Management

Brush removal along the moat bank and the mauka rock wall was completed in August.

Relatively few mangrove seedlings were removed these months possibly due to low water conditions limiting transport. A mangrove eradication project was completed along the mauka edge of the lake between the dock area and the end of the wetland property line. This has reduced the rate of seed pod deposition in the lake.

The native plantings near the dock continue to grow. The Bulboshonus sp. planted along the moat edge near the mauka road have grown rapidly where planted in very wet spots. These have begun to spread and produce seed heads. A patch of Cyperus sp. sedges was found along the makai bank of the stream channel, near Al’s dock. This population of naturally occurring sedges is being weeded and nurtured for future distribution to other areas.

Predator Control and Predation

Live trapping for rats, cats, and mongoose was not conducted during this period. It is believed that the baiting controls rats effectively and that neither mongoose nor cats occupy the wetland.

Frog Control

Bullfrogs were captured using a single 20 inch funnel trap constructed June 17th. After 77 days of continuous use a total of 7 frogs were captured. The weekly average rate is 1.56 frogs per trap-week. During two weeks in August the weekly rate was 2/wk, possibly indicating population growth. One frog caught in the week of 8-28 was a gravid female with early stage eggs.

Rat Control

Eleven bait stations with diphacinone based baits were deployed around the wetland and three were deployed on the adjacent dryland property. These stations were checked and refilled weekly, or in the case of the dryland stations, twice a week. It was determined that re-evalution of the protocol would be recommended if a station was cleaned out (over 100 g bait eaten per week) for two consecutive weeks. This never occurred in the wetland although consumption rates did vary over time from place to place. The stations were cleaned up and old bait discarded monthly.

Opala Patrol

Trash and spray paint cans were collected semi-weekly during the period. Few spray paint cans were collected and little trash. This was attributed to low flow rates down the stream and the storm drains during this dry period. If spray painting in culverts is done during the school year then a low influx rate during the summer would be expected.

Bird Observations

Species of Note

Koloa and wandering tattlers migrated back in August. A formal bird count was conducted on August 17th By Cindy, Hugo, and Larry. No unusual sightings were made.

No stilts with oysters attached to their feet were observed in July and August. There was a report of one trapped elsewhere in the lake that had later escaped and of one, possibly the same bird, that had a broken leg. This bird is still alive and has been seen feeding near Kukilakila.

Breeding activity

After 3/1, regular inspection of nests on the islands was suspended per the USACE instructions to stay off of the islands where stilts may be nesting. Nest observations are more sporadic as a result. The number of nest sites found since April is an undercount.

Feral Birds

The goose flock continues to be tended at the house at the end of the wetland. These birds rarely feed in the wetland.
Mallards have successfully hatched three or four broods in July and August. One brood that was observed the week of 8-21 had five juveniles. None of those seen prior to then had any survivors after a couple of weeks post hatching as far as we could see.

Native Birds

The Stilts hatched May 20th were seen flying on August 1st , about 10 weeks after hatching. Two survived to this age from the original 4 hatched on island one. Of these two juveniles one remains in the wetland with its parents. The other stopped returning to its resting area in the evenings on the week of 8-21. Its disposition is not known.
The other four stilt chicks, from island two, survived just a couple of weeks or less after hatching. Their disappearance was indicated by the cessation of the parent’s defensive behavior. They hatched on island two between 6/27 and 7/1. Because the home territory of these birds was far more overgrown with vegetation they were difficult to monitor. Why did they die? This second pair of parents may have been less able to protect their wandering chicks because the taller vegetation hid the chicks and their predators from the parent’s view.

On the week of 7-10 two broods of coots hatched and two broods of gallinules hatched. These were both probably second broods for these pairs this nesting season. After them there were no other new broods observed. Survival to this date, 9-4-05, is 25 to 50 percent for each or one or two chicks now reaching about 7 weeks of age.

Locations of Nest Sites

The locations of the four nest sites is not known but the coots occupy territories in the stream channel and the moat channel near the road. The gallinules are more cryptic but seem to occupy the stream and the stream mouth and Island One near the stream.

Submitted, 9/4/05
Larry Abbott

Known Nest Sites for 04-05 Season

Coots:
C1- Rebuilt nest by pair flooded earlier on island one. Five eggs observed on 2/12.
C2- Rebuilt nest by pair flooded earlier on island three. This earlier nest had one dead chick. On 2/7 two chicks had hatched and three eggs were not yet hatched. No eggs were in nest on Friday so all probably hatched. Parent on nest has a red spot on face shield.
C3- Rebuilt nest by pair flooded earlier. All four eggs hatched and chicks were seen at the nest and elsewhere by Bill.
C4-New nest discovered two weeks ago, may not be active.
C5-New nest. Five eggs were observed on 2/12
C6-New nest site. No eggs observed.
C7- Nest site where two drowned eggs were found 3/21.
Gallinules:
G1- Gallinule nest with 6 eggs found 2/28
G2- Gallinule nest with 2 eggs found 2/28
Goose- 16 eggs oiled on 2/21 and again 3/21, a nest with an unknown number of eggs produced at least three white goslings early in June. Survival was down to one within a month.
M- mallard nests since September