Showing posts with label Biological Reconnaissance. Show all posts
Showing posts with label Biological Reconnaissance. Show all posts

Friday, August 26, 2016

On my own behalf: Middleton Island, Gulf of Alaska (May 15 - July 15, 2016)

I recently spent some time on Middleton Island, a small (2x8km) and remote island in the Gulf of Alaska, in order to take care of some unfinished bussiness. It all went fairly well. This post contains an almost random selection of photos taken during my stay, as well as some words that touch the subjects of my work only slightly. More will come out eventually, but will need to be published on paper first…




59°29’N, 146°28’W is our destination…





The northern airstrip, facing south.





Sealions (mainly Northern Sea Lions Eumetopias jubatus and fewer California Sea Lions Zalophus californianus got recorded during my stay) made a comeback to the island a few years ago. Well, they try to make one, but regular human disturbance was likely the reason for them to abandon the north spit this summer and hang out on some smaller rocks offshore. This photo was taken during my single visit to the potential rookery, from larger distance than what was kept by most other island visitors… (perhaps time for some regulation here?)








The cliffs and slopes continue to erode. The past few years several landslides occurred, one of which took this large Red-berried Elder Sambucus racemosa (a well-known specimen for the older generation of seabird researchers, it was the one in use as boundry marker during counts) from the cliff at the south end and deposited it in the current lowland, where it was found flowering.





Most of Middleton’s largest Sitka Spruces Picea sitchensis appeared to be in poor condition. The oldest generation (now around 120 years old) are decaying and regeneration did not seem to occur within the past years. The monumental tree at the FAA headquarters blew over last winter, but its currently being held up by ropes.





The island’s Bald Eagle Haliaeetus leucocephalus population was booming; no fewer than seven pairs nested (six was the previous record). The platform pair raised three chicks this summer, while the NEXRAD radar on the left underwent major renovation. The first eagle pair nested on Middleton in the mid 1980's.











As usual, a few immature eagles remained on the island this summer, often harassing the kittiwakes in the former A.C.&W. station. There seems to be some movement among these birds, as some left and new ones appeared in the middle of the summer. I found one flying many miles offshore west of the island, eventually arriving to the island's north end. During the last days of June an adult bird arrived which was later seen battling with several of the breeding birds regularly, as it was trying to fight its way in the population.











If there’s one bird I can’t get enough of it’s the Tree Swallow Tachycineta bicolor… Only four pairs occupied the nest boxes this summer, fledging 18 banded chicks. Several unpaired males occupied boxes as well. There was still a lot to learn from those birds and a full report about the 2016 breeding season will appear on this blog hopefully this fall.








View from the largest tower within the former A.C.&W. station, facing south...





Facing northeast.








Middleton once held one of the largest Black-legged Kittiwake Rissa tridactyla colonies in the world. Their number dropped quite a bit during the past decades. On my last visit to the island in 2010, much of the southwest cliff was still occupied by them. This summer the few kittiwakes nesting on boulders in the lowlands exceeded the number nesting on the cliff.




A movie of this Wilson's snipe Gallinago delicata facing variable wind directions would have been a lot funnier, I guess…





My best shot of a Killer Whale Orcinus orca (or Loch Ness Monster?) while it was on a hunt for seals.





I spent a lot of time scoping out >10.000 Glaucous-winged Gulls Larus glaucescens in their breeding habitat, suspecting there had to be a different species of gull in there somewhere (besides Mew Gulls). I wasted my time and found none.





Never did I see so many white feral rabbits on Middleton. In the first decades after their introduction in 1954, white remained one of the dominant colors. Natural selection probably changed something (in particular after the appearance of Bald Eagles in the 1980’s?). Strange to see so many, while at the same time the eagle population experienced a record high. This individual was taken care off by a Glaucous-winged Gull, who’s appetite for Middleton’s rabbits appeared larger than before.








It always seems like the whole world comes together in a Black Oystercatcher Haematopus bachmani nest. Every Zen garden should have one.





Presumed Japanese tsunami debris, providing a shelter for rainy moments after counting the island's entire oystercatcher population.





Every year a new boat washes up. This is the latest addition to the Middleton fleet. Fancy...





The rusty remains of the WWII era cargo ship U.S.S. Coldbrook are still holding up… Sydney, seen here from the back, maintained a blog about her experiences on the island (and will do so again next year?). Check out the link to that somewhere on the right.





The presence of a Bald Eagle nest on the Coldbrook’s mast detered many Common Murres Uria aalge and Pelagic Cormorants Phalacrocorax pelagicus from nesting on or inside the wreck. It was obvious that most of the 1000+ Common Murres present this summer did not breed due to regular eagle disturbance.





Inside the back of the ship an old Common Raven Corvus corax nest was found (center back in the photo, now containing kittiwakes). Ravens made their first appearance on Middleton during winter 2009/10. Two were present this summer, but no nest was found.





The South Spit





A handful of Mew Gulls Larus canus nested on the spit. They’re easily distinguished from kittiwakes as they lack a soul.








After a mild winter, Pacific Wrens Troglodytes pacificus were extremely abundant. It appeared that all available habitat was occupied this summer. On good wren-years, accumulated driftwood on the South Spit is known to hold a single territory (note the singing bird on the first photo). This year two males were singing there regularly. Numerous nests were found in the driftwood this year (incl.one inside the largest trunk on the second photo). I recall that after a cold winter, in 2006 only a few singing birds were heard. There are some unconfirmed reports of a die-off.





Part of the vegetation study I’m conducting are several exclosures, which are small fenced off squares allowing me to monitor the development of the vegetation in absence of the island’s herbivores. Previous winter several storms damaged the already rusty chicken wire, allowing some rabbits to enter. Thankfully this happened outside the growing season so no real harm was done to the project. Every summer a few uncommon plants grow within the exclosures. As in 2010, this Unalaska Paintbrush Castilleja unalaschcensis grew at the same place inside the same exclosure at the north end. The only other paintbrushes noticed in that area were the ones used by the contractors renovating the NEXRAD.





During summer the rabbits eat most of the island’s flowers. Besides growing within an exclosure, there are several other ways in which plants manage to remain present on the island. Some of them are simply too beautiful to get eaten, like these Few-flowered Shootingstars Dodecatheon pulchellum…





Wild-flag Iris setosa





Fischer's Orchid Dactylorhiza aristata








Some plants fight back: the known patches of the carnivorous Round-leaved Sundew Drosera rotundifolia, just north from the Dwarf Forest, were still there (and increasing?)





I was hoping to put a bit more effort in social hygiene during my stay this time, by taking a plunge in some of the island’s fresh water. Too bad Leeches Hirudenea sp. recently found their way to Middleton (at least I never noticed them before). They now occur in pretty much all fresh water bodies present on the island.





Lapland Longspurs Calcarius lapponicus are birds of the alpine tundra, but Middleton's north end still provides suitable breeding habitat to 8 – 9 pairs counted there this year. They were a bit more common during previous visits between 2005 - 2010, when territories were also found along the gravel roads further to the south.





This is as close as I wanted to get to the pair of Red-throated Loons Gavia stellata in the Loonpond. The first recorded nesting of this species took place here in 2005. In 2010 a second pair showed up along the east, in a pond at the end of the Dump Rd, but it did not nest. This summer no fewer than four pairs were present, at least three of which nested and these were all seen with chicks. Red-throated Loons are on Audubons’ 2016 Watchlist, so I informed them about this positive development.





Yellowlegs sp… Tringa sp. in the Military pond. I didn’t spend a lot of time looking for migratory species (the timing of my stay was well off for experiencing fall migration). However, I was informed that up north the ice melted early this spring, allowing many shorebirds and waders to move into and depart from their breeding areas relatively early this year. That may have been the reason why I still managed to get my share during the first half of July.





July 4: low tide 07:47 AM -98 cm (predicted), northeast intertidal area.





Whatever is left of one of the exposed fossil banks in the northeast, containing large numbers of marine shells. Only visible during the lower tides.








Chamisso's Cotton-grass Eriophorum chamissonis, on a late summer evening.





It was a fantastic experience being able to connect with Middleton again this summer, to be able to observe how things change in nature and understand the different timescales on which it all takes place. And find a few new things along the way... It was also very nice to meet up with some old friends I hadn´t seen in years and make some new international contacts as well. Thank you all for making my time on Middleton an escapade I shall not forget. I hope I manage to get out there again at some point in the future.

Monday, July 30, 2012

The 1956 Biological Reconnaissance of Middleton Island. Part 1: Marine Shells of Middleton Island, Alaska.




As mentioned in the previous blog entry, Middleton Island got the attention of science at a relatively early point in time. Due to its unique location and well preserved geological features, over the years the island attracted the attention of many geological researchers. Middleton Island, located near the margin of the continental shelf in the northern Gulf of Alaska, has emerged from the sea during several major episodes of co-seismic uplift of about 7 m, 8 m, 6 m, 9 m and 7.5 m, which are recorded by marine terraces. These uplifts have been dated at roughly 4,300, 3,800, 3,100, 2,390 and 1,350 radiocarbon years before present, respectively. The most recent uplift took place during the 1964 Alaska Earthquake, when on March 27 the whole island got lifted up another 3.5 m on average (Plafker & Rubin 1978).

In contrast with the geological interest the island has received during previous decades, the number of biological studies conducted on Middleton that have a clear relationship with the island is relatively small. Thus far the most important moment in the recorded natural history of Middleton took place in June 1956, when a field party consisting of Dr. Norman J. Wilimovsky (U.S. Fish and Wildlife Service), Dr. John H. Thomas (Stanford University) and Robert Rausch (Arctic Health Research Center, Public Health Service) undertook a biological reconnaissance of Middleton Island. Their visit had been arranged because of military activities on the island (at that time there was a large scale Cold War radar station under construction) were likely going to cause imminent disruption of the island’s natural relationships. This made it desirable to record as much as possible of the island’s natural history before the opportunity was lost. Their work was supported mainly by the Office of Naval Research and the United States Air Force, but additional support was provided by the Arctic Research Laboratory, Stanford University and the Arctic Health Research Center. These studies were aided by a contract between the Office of Naval Research, Department of the Navy, and the Arctic Institute of North America (Rausch 1958).
As far as I could see the 1956 biological reconnaissance resulted in three publications. Robert Rausch described the island’s avifauna in “The Condor” in 1958 and John Thomas published his story about the island’s vegetation in “Contributions of the Dudley Herbarium” in 1957. During their stay in 1956, the party also assembled a small collection of mollusks from the intertidal area, which had been submitted to the California Academy of Sciences for identification. Eventually G. Dallas Hanna and Leo George Hertlein identified the marine shells and these were listed and described in 1959 in “The Nautilus, The Pilsbry quarterly devoted to the interests of conchologists marine shells”.  

During my first stay on Middleton Island in 2005, however, I noticed that during recent decades little had been published about the general wildlife of the island and that the available works about the vegetation and avifauna (Thomas 1957; Rausch 1958) were largely outdated, especially due to some severe (a-)biotic changes that occurred during the decades following these publications. For me this was a good reason to start several studies on Middleton Island’s wildlife, focusing on the development of both vegetation and avifauna, in particular breeding birds. These studies started a year later and are keeping me pretty occupied up to the present day.
With this blog entry, the first of a series of three, I want to focus on the results of the 1956 biological reconnaissance of Middleton Island and share with you some of my thoughts on these and maybe present some preliminary results of my own studies in relation to these.
This first entry, however, is about a subject I know very little about and I can’t write much about either: the marine shells of Middleton Island. Now it already took me a considerable amount of time and effort some years ago finding a copy of Thomas’ 1957 vegetation study, I never managed to find a complete copy of Dallas Hanna’s and Hertlein’s work on the identified marine shells of Middleton Island. Until yesterday that is! The good news is that the whole edition of The Nautilus is now freely available online:





Dallas Hanna and Hertlein write about the collected material: “Twenty-one species are present in the lot and also one barnacle. To these may be added for reference purposes, two additional species cited by Dall (1921, pp. 32, 107) from Middleton Island. Thus the known marine mollusks from this island consist of 5 pelecypods, 14 gastropods, 3 chitons, 1 cephalopod and one barnacle. All, with one possible exception, are known to occur in waters of this general region at the present time. However, this one, Littorina arctica, may have been cited in Alaskan literature under a different name.” (Dallas Hanna and Hertlein 1959)

Now does this mean that the subject has been studied enough by now? Certainly not! Dallas Hanna and Hertlein already give two reasons why further study of the molluscan fauna could be very interesting:

“A geological investigation of the islands has been made by Don. J. Miller (1953), of the U. S. Geological Survey. During the course of his work he obtained 20 species of mollusks (identified by F. Stearns MacNeil) from Pleistocene sedimentary beds. Oddly enough, none of these species was found in the collection being considered here. It is practically certain that the lists of both fossil and recent species represent only a small portion of the total molluscan fauna of the island and adjacent waters.” (Dallas Hanna and Hertlein 1959)

Now I can come up with several more reasons to show some interest in the intertidal life around Middleton Island:

-  After the 1956 biological reconnaissance the 1964 Earthquake lifted up the whole island about 3.5 m on average, creating a new and more extensive intertidal zone around the island. This meant that the area that had initially been inspected by the 1956 field party currently makes up a permanent part of the island and does not contain live marine mollusks anymore. How did the new intertidal zone develop?

Intertidal area at the island's south end in 1960 (photo: Armand Biron)

Intertidal area in the upper east part of the island in 2005. No clear intertidal zone 
could be identified here before the 1964 Earthquake (photo: T. van Nus).


- The island remains under constant influence of seismic activity in the area, resulting in a small but continuing uplift or tilt (Prescott, W.H. and Lisowski, M. 1977; personal observations). It would be interesting to find out how over time this uplift affects the occurrence of mollusk species in the area

- Personal observations of the current intertidal zone indicate that this area can make up about half of the total size of the island itself (which is about 2 x 7.5 km). The new intertidal zone has become a majorly important foraging area for both breeding birds as well as a large number of spring and fall migrants, in particular shore birds. Very little is known what these birds find there and whether the availability of food is a limiting factor for them.

- Personal observations also suggest that intertidal life can be diverse but there are large annual changes occurring; in example the growth of kelp sp. varies a lot among years. Sea Otters (Enhydra lutris) established themselves for the first time in recorded history in the winter of 2008/2009 (van Nus, personal records). What is going on here?


Sea Urchins were very common during my first visits to Middleton in 2005 but were not 
seen often during later visits. At the same time growth of Kelp appeared to increase 
(photo: T. van Nus).


Now I never managed to find enough time to put effort into a study of the intertidal life around Middleton Island and I believe the challenge is still there, but it better needs to be done soon before another opportunity is lost..!


Literature

Miller, D. J. 1953. Late cenozoic marine glacial sediments and marine terraces of Middleton Island, Alaska Journal of Geology, 61:17-40.

Plafker, George, and Rubin, Meyer, 1978, Uplift history and earthquake recurrence as deduced from marine terraces on Middleton Island, Alaska, in Proceedings of Conference VI, Methodology for identifying seismic gaps and soon-to-break gaps: U.S. Geological Survey Open-File Report 78-943, p. 687-721.

Prescott, W.H. and Lisowski, M. 1977. Deformation at Middleton Island, Alaska, during the decade after the Alaska earthquake of 1964 Bulletin of the Seismological Society of America June 1977 67:579-586

Rausch R. 1958. The occurrence and distribution of birds on Middleton Island, Alaska. The Condor 60: 227-241.

Shepard Oldroyd, I. 1924 – 1927. The Marine Shells of the West Coast of North America.
Four Volumes. Stanford, California. Stanford University. 1520 pp. illus. ISBN: 9780804709873

Thomas, J. H. 1957. The vascular flora of Middleton Island, Alaska. Contrib. Dudley Herbarium, 5:39-56.


 Scattered boulders along the western shoreline (T. van Nus).