Wildlife Inventory Plan Alaska Maritime National Wildlife Refuge Protocol #27 Version 1.2 Parameter: Productivity (black-legged and red-legged kittiwakes); populations (marine mammals) Species: Black-legged and red-legged kittiwakes; marine mammals PURPOSE To determine minimum productivity estimates for black-legged and red-legged kittiwakes on Otter Island. In some years, to count marine mammals from land (if permission to land on the island is granted). STUDY AREA Otter Island (57 o 02 N, 170 o 24 W) is approximately 7.5 km south of St. Paul Island (Figure 1). Surveys are conducted from skiff and sometimes from land. Otter Island is a haul out for Northern fur seals (Callorhinus ursinus), harbor seals (Phoca vitulina), and Steller sea lions (Eumetopias jubatus), so appropriate measures to avoid disturbance must be taken. When surveying from skiff, keep an eye out for marine mammals and stay far enough offshore that they do not react to your presence. If they start swaying their heads and moving to the water, you are disturbing them and you should back off: do not gun the engine and proceed at a slow even pace. The majority of seals and sea lions occur on the northfacing beaches, whereas the seabird plots are on the northeast and east cliffs so disturbance is usually minimal. The reef that abuts plot 1 often has harbor seals, so proceed cautiously here and do not gun the engine. Counts of marine mammals on the south side of the island are best conducted from land. However, do not land on Otter Island unless given permission by the unit biologist. If you are given permission to land on the island, the only place you can access the interior of the island is from the north beach. It is best to moor the boat along one of the lava flows (Figure 2). Check and secure shackle connections on the anchor chain. Deploy a tube buoy or air roller to serve as a bumper against rocks. Do not moor the boat where it will be bumping against barnacles, they can pop the pontoons! If you are going to walk around the island put your survival suits on shore just in case your boat gets away. PROCEDURES BOOM-OR-BUST KITTIWAKE PRODUCTIVITY Data collection. Boom-or-Bust productivity estimates at Otter Island are generated during two visits by boat. Timing of visits should be based on weather and nesting chronology each year, which can be estimated from chronology on St. Paul (as black-legged kittiwakes are most numerous, use their timing as your main indicator). The first visit documents maximum reproductive effort and should be timed for the period when all the nests are built but before many nests are lost during the incubation period. Ideally this is within a week following peak laying; a good rule of thumb is 15 to 25 days after the first egg on St. Paul. The second visit captures how many chicks hatched from the nests counted earlier and should occur when most chicks are large enough to be seen in the nests (from below) even if still being brooded, generally 3 to 4 weeks after peak hatch (or 4 to 6 weeks after first hatch). When planning visits watch the long term weather forecast - if a big low pressure system is coming and may make for perilous boating conditions for an extended period of time, you may have to go earlier or later than what is ideal to fit in counts. Before the first visit, spend some time at St. Paul learning to distinguish black-legged and redlegged kittiwakes and their respective nests. At Otter Island you will have to identify unattended nests to species, based on the appearance of the nest. Black-legged kittiwake nests are generally larger and 27-1
composed of more vegetation, whereas red-legged kittiwake nests tend to be less substantial mud platforms. Red-legged kittiwake nests may also be under ledges and are more likely present in areas of higher red-legged kittiwake abundance. Keep in mind this is not a perfect system; you are going to have to make some judgment calls. The more time you can spend studying nests at St. Paul beforehand, the better your data will be. All counts are conducted from a skiff using 10x40 binoculars. It works best to have the most experienced boat operator drive the skiff, and with 1-2 observers. Counts are performed on nine preestablished plots on the north and east side of the island (Figure 3). On the first visit: on each plot, first count the number of kittiwakes for each species, then count the number of active nests for each species (see Figure 4a). A nest is defined as any structure to which vegetation has been added in the current year. You will have to use your best judgment as to whether the nest is active (has been added to) this year or not, particularly when the nest in question is just a few strands of material on a ledge. Just do your best and move on. All birds and nests should be designated as one species or another; do not record unknown kittiwake. The data from the first visit provide a population index (adult birds) and a measure of initial reproductive effort to act as a denominator in our estimate of reproductive performance. There is no need to record nest contents (incubating birds, eggs visible, etc.). On the second visit, count the number of adult kittiwakes for each species, then separately count the number of nests containing 1, 2, or 3 chicks for each species (from this, you can calculate both the number of nests with chicks and the total number of chicks; see Figure 4b). There is no need to count nests without chicks on this visit. It can be difficult to identify chicks to species when not attended by an adult. Data from the first visit are helpful in making these determinations. If there were no black-legged or red-legged nests in the plot, or if all the nests for one species are already accounted for, you can make an educated guess as to the species based on nest structure or data from the first visit (i.e., if all nests in a plot belonged to just one species on the first visit). During both visits, it is important to note sea and weather conditions, as well as any changes in the plots (landslides, etc.). These may be important in comparing data among years. If possible, also make notes of any other bird species observed for inclusion in an annotated list. Data analysis. Estimate reproductive success for each species by calculating the following from your raw data: Total nest starts (A) number of nest sites counted during early surveys/counts Nest sites with chick (D) number of nest sites containing any chicks Total chicks (E) total number of chicks seen From the above values, calculate the following summary parameters: Mean brood size (E/D) Proportion of nest sites with chicks (D/A) Chicks per nest start (E/A) PROCEDURES LAND-BASED COUNTS Data collection. If you are given permission to land on Otter Island, conduct land-based counts of marine mammals on the island. Fur seals generally hang out inland around a brackish pond. Walking a wide arc around the fur seals, go to the ridge south and east of the pond. Count from a spot denoted by a small house pit (where the Seal Sheriff of days gone by was posted) - this vantage point allows you to look down on the reef abutting plot 1 (to count harbor seals) and also provides an unobstructed view of the pond area (to count fur seals). In addition to conducting marine mammal counts, find and photograph a large offshore rock off the southern coast covered with common murres (Uria aalge; Figure 5). This photograph can be used to count murre numbers. 27-2
Specific Requirements Dates: First visit within a week of peak lay dates at St. Paul (generally 15 to 25 days after first egg; usually mid- to late June). Second visit three to four weeks after peak hatch at St. Paul (usually late July). Location: Nine plots on the north-east side of Otter Island (plots 1-5 on the north side and plots 6-9 on the east side). Weather: Calm seas and good visibility, both for counting ease and boating safety. Equipment: All boating safety gear, 10x40 binoculars, plot maps, two sets tally counters, Rite in Rain data notebook (with data from first visit), two pencils, digital camera. 27-3
N Figure 1. Map of St. Paul, Otter and Walrus islands. 27-4
Figure 2. Views of skiff mooring location at the northern beach at Otter Island. 27-5
West South Skiff mooring site North East Kittiwake Boom-or- Bust Plots 6,7,8,9 Northeast Kittiwake Boom-or- Bust Plots 1,2,3,4,5 Figure 3. Aerial view of Otter Island showing Boom-or-Bust plot areas for kittiwake productivity. 27-6
a b Figure 4. Example field notebook layout for Otter Island data for (a) first and (b) second visits. 27-7
Figure 5. Offshore rock off southern coast of Otter Island with common murres. 27-8
Protocol Revision History Log Protocol Revision History Log Revision Date Changes made New version # April 2017 Renumbered protocol from #24 to #27, minor grammatical corrections 1.2 April 2014 Changed font to Arial, added revision history log, replaced revision date with version # on first page, added protocol # to first page, changed number format of tables and figures in island attachments, changed page number format to include protocol # May 2011 Protocol developed in standardized format from historic St. Paul protocols 1.0 1.1 27-9