Both Graylag Goose (Anser anser) and Swan Goose (A. cygnoides) have a long history of domestication and hybridization with each other. The extensive hybridization of these two domestic geese often makes it impossible to determine for certain if a given individual is truly "pure." However, visual field marks can help one to determine an individual's identity to a degree that's frequently "accurate enough" for citizen science if not perfectly accurate in some cases. Below I will discuss some helpful features for identifying these species and their hybrids. Everything discussed below is referring to the domestic forms of both Graylag and Swan Goose rather than their wild-type counterparts.
Plumage
Although many domestic geese are mostly or totally white, I think it's important to first discuss some basic plumage characteristics of these two species when they are "normally" colored.
Graylags will often be grayish brown with a mostly monotone neck that is usually darker than much of the body. The neck feathers typically have more "ruffles" than Swan Geese. The ruffles appear more textured and look like lines in the neck feathers.
Swan Geese have more of a two-toned neck, with a richer brown "mane" running along the entire back of the head and neck. Swan Geese also tend to have a smoother neck than Graylag, without the aforementioned "ruffles."
Hybrids of the two species are variable, but show a mix of the characteristics from both species. Oftentimes they have a "mane" similar to pure Swan Goose, but more faded and less distinct. They will also often show more neck "ruffles" than pure Swan Goose.
Bill
The bill is possibly the most helpful feature for identifying these species. Graylags have bright orange or occasionally pinkish bills. Swan Geese without any white in their plumage seem to almost always show black bills, while Swan Geese with more white can show partially/completely orange bills.
Swan Goose bills are often proportionally larger compared to their heads, with a large "knob" at the base of their upper mandible. Graylag Goose bills are often smaller proportionally and don't have a knob at the base. If a goose looks otherwise like a Graylag, but has any kind of knob on the bill, it can be assumed that it's a hybrid. If a goose looks otherwise like a Swan Goose, but has a reduced knob, it's often safe to assume it's a hybrid.
Structure
Graylags are often more compact while Swan Geese are often more lanky, the latter having longer necks in relation to body size. The heads of Swan Geese tend to look longer than that of Graylags.
Note the darker and often broader cheek patch, brighter orbital, orangey bill, browner head and neck, and duller plumage when compared to pure Canada Goose.
When this hybrid lacks its plumage features, however, it becomes more of a challenge to ID.
Graylag x Canadas tend to have smaller, thinner bills than pure Graylags. Their overall proportions, especially those of the body and neck, are often more thin and dainty than Graylags. Their proportions more closely resemble that of Canada Goose.
Swan x Canada Goose hybrids are similar to Graylag x Canadas but with longer heads, and typically a knob at the base of the upper mandible. They also typically have black bills and lankier proportions.
Both Graylag and Swan Geese tend to have a more or less straight vertical border between the bill and the feathers. The images on the left are about the most variability one will see in this trait (bottom left is a wild-type Graylag Goose but this feature remains consistent). Canada Geese have a more pushed in shape to the base of the bill, which translates to hybrids. Hybrids tend to be intermediate in this characteristic. If an all white goose has a thinner bill with a similar pushed-in shape to its base, it's a hybrid.
I don't recall coming across photos of any completely white Swan x Canada Geese, but oftentimes they will have large solid chunks (or thick "bars") of white on their underparts.
The above individual is likely the product of all three species. It is probably something along the lines of (Swan x Graylag Goose) x Canada Goose. Note present but limited bill knob, mostly orange bill, and intermediate proportions.
As I mentioned above, it's important to keep in mind that not all individuals are identifiable. Many are best left at Graylag/Swan Goose or Graylag/Swan x Canada Goose. Both Graylag and Swan Goose hybridize with other species than those mentioned here, but the ones I discussed are the most common, and are frequently an identification challenge. Thank you @that_bug_guy for the input on this guide.
Below are some examples of the variability of Graylag x Swan Goose hybrids.
In summary:
Graylag Goose - Uniform gray, distinct neck ruffles, orange bill, no knob, often heavy-set
Swan Goose - Cream with contrasting "mane," no neck ruffles, large knob, often slim
Graylag x Swan Goose - Intermediate; faded "mane," two-toned bill, reduced knob and neck ruffles
The full hybrid index was compiled mostly using eBird and Avian Hybrids. Some hybrids listed by these sources don’t have photos or information online that I was able to track down, which is why some of these taxa don’t have individual sections in the guide dedicated to them. Contributions for these taxa especially are extremely helpful, but information on nearly all hybrids is lacking so any information or media is important. If you notice any errors or have something to contribute please leave a comment or send me a message.
Compiling a list of all known hybrids with examples is difficult for several reasons. Obviously I'm not able to obtain permission to embed all media of these hybrids on a single web page/journal post. This means I'm relying on countless other sites to continue to host said media for the foreseeable future. This will inevitably lead to broken links and lost media. Uploading to sites like iNat and eBird can hopefully prevent this.
The full hybrid index was compiled mostly using Bird Hybrids, eBird, and Avian Hybrids. Taxa that have been said to exist but that I wasn't able to find photos or information on are listed in the index but have no section dedicated to them yet. Contributions for these taxa especially are extremely helpful, but information on nearly all hybrids is lacking so any information or media is important. If you notice any errors or have something to contribute please leave a comment or send me a message.
Compiling a list of all known hybrids with examples is difficult for several reasons. Obviously I'm not able to obtain permission to embed all media of these hybrids on a single web page/journal post. This means I'm relying on countless other sites to continue to host said media for the foreseeable future. This will inevitably lead to broken links and lost media. Uploading to sites like iNat and eBird can hopefully prevent this.
White-backed Night Heron (Gorsachius leuconotus) White-eared Night Heron (Gorsachius magnificus) Japanese Night Heron (Gorsachius goisagi) Malayan Night Heron (Gorsachius melanolophus)
eBird iNat Photos (Note: in these photos it appears that the bird is doing the classic wing-flicking and open-wing foraging behavior that Reddish Egrets do.)
All I can find is this photo (you may need a bird forum account to view it) from this discussion regarding its ID. All other links to images in that thread appear to be unfortunately broken.
The full hybrid index was compiled mostly using Bird Hybrids, eBird, and Avian Hybrids. Some hybrids listed by these sources don’t have photos or information online that I was able to track down, which is why many of these taxa don’t have individual sections in the guide dedicated to them. For these taxa without evidence, it's unclear if many of them ever existed or are even possible. Contributions for these taxa especially are extremely helpful, but information on nearly all hybrids is lacking so any information or media is important. If you notice any errors or have something to contribute please leave a comment or send me a message.
Compiling a list of all known hybrids with examples is difficult for several reasons. Obviously I'm not able to obtain permission to embed all media of these hybrids on a single web page/journal post. This means I'm relying on countless other sites to continue to host said media for the foreseeable future. This will inevitably lead to broken links and lost media. Uploading to sites like iNat and eBird can hopefully prevent this.
Key: ✅- Certainly or nearly certainly is produced in the wild
⏺- Likely can be produced in the wild
(Note: I'm not extremely familiar with the introduced populations of waterfowl in a lot of places, especially Europe, so take these icons with a grain of salt.)
https://macaulaylibrary.org/asset/38865421 Five backcrossed ((WHOS x TRUS) x TRUS) offspring (center) with Trumpeter Swan parent (left) and hybrid (WHOS x TRUS) parent (right).
https://macaulaylibrary.org/asset/37814191 Four backcrossed hybrid offspring ((WHOS x TRUS) x TRUS) with Trumpeter Swan parent (left) (same individuals as above).
NOTE: Pure American Black Ducks frequently show a slight green iridescence on part of their head (like this bird). Hybrids tend to show a significant amount of green. The presence of just a small amount does not necessarily indicate Mallard involvement.
Pure American Black Ducks frequently show a thin white border to the posterior edge of the speculum (like this bird). The presence of white in this area does not necessarily indicate Mallard involvement. Hybrids tend to show a more extensive white posterior border to the speculum. Hybrids also tend to show a white anterior border to the speculum.
Female pure Mallards frequently show an olive-colored bill (like this bird). Greenish bill coloration on the bill does not necessarily indicate American Black Duck involvement.
Pure American Black Ducks don’t tend to show truly white tail feathers, however edges of worn feathers can appear lighter than normal.
Beware: Male Mallards in eclipse plumage (as well as other molts/odd plumages) can get easily mistaken for this hybrid.
eBird There are some presumed hybrids on Macaulay Library based on what seem to be the parents nearby, but the hybrids in question seem to appear phenotypically identical to Gray Teal to my eye. Could the Chestnut Teal not be a biological parent? I don’t know enough about this to suggest anything myself so one can come to their own conclusions.
This seems to be the most credible evidence for any hybrid involving Mandarin Duck. All other alleged Mandarin Duck hybrids that I've come across either don't have any credible evidence or, in the case of Mandarin x Wood Ducks, are just eclipse plumage male Mandarin Ducks. No other Mandarin Duck hybrids in the paper below seem to actually be Mandarin Duck hybrids.
Research Paper ⏺
Photos - See the description on this photo for more information. Yellow-billed Duck is not certainly ruled out for the other parent but I thought I should include this regardless.
Photos This bird certainly has all three species in it. If I understand correctly, it is likely ((Snow x Bar-headed Goose) x Swan Goose) x (Snow x Bar-headed Goose). In other words: 37.5% Snow Goose, 37.5% Bar-headed Goose, and 25% Swan Goose.
Photo
Photo Photo Photo Photo From my understanding these birds are the result of a pure Graylag Goose breeding with a tri-species hybrid. Something like Graylag x (Swan x (Bar-headed x Snow)) Goose. See their likely parents here.
Blue-winged Teal x Northern Shoveler (BWTE x NSHO) and Cinnamon Teal x Northern Shoveler (CITE x NSHO) are two hybrid taxa that are frequently confused with each other. Blue-winged x Cinnamon Teal is another somewhat similar hybrid but they're easy enough to separate from these other two hybrids so I will not be discussing them here.
Beware of staining! Some birds can be stained a rusty color from the water or environment that they exist in. This can make a few of the below field marks more challenging to determine.
Note: Remember to use more than one field mark to identify an individual. It is especially important with hybrids to not use one odd-looking feature to rule something out completely.
Breast The breast of BWTE x NSHO is paler overall than that of CITE x NSHO. The main color is a pale off-white to a pale buffy/orangey. The breast of BWTE x NSHO is covered in dark, well-defined speckling and patterning.
The breast of CITE x NSHO is a darker and richer orange/cinnamon coloration overall. The main color is a pale cinnamon to a rich dark orange, contrasting less with the flanks than that of BWTE x NSHO. The breast of CITE x NSHO is often covered with less-defined and more messy dark patterning/speckling, but is frequently nearly completely patternless and monochrome in color. Compare a few individuals below.
Flanks The flanks of BWTE x NSHO are often paler and not quite as rich of a cinnamon coloration as CITE x NSHO. BWTE x NSHO flanks are also often covered in well-defined black speckling and patterning. The flanks also often obviously contrast heavily with the pale breast.
The flanks of CITE x NSHO are often darker and richer cinnamon in coloration. The flanks seem to be almost completely patternless in most cases, with the occasional small amount of speckles or stripes visible, but never as extensive or obvious as on BWTE x NSHO. Compare some individuals below.
Hip Patch The hip patch of BWTE x NSHO is white. It usually lacks any rusty coloration unless it's stained.
The hip patch of CITE x NSHO is anywhere from white to cinnamon, but it frequently has at least some cinnamon wash on it. Compare some individuals below.
Cheek Patch Oftentimes people will use the fact that a given individual has a white crescent at the base of its bill to suggest that Blue-winged Teal has to be involved. This is not the case. Both BWTE x NSHO and CITE x NSHO have this white crescent. In fact, BWTE x NSHO seem to frequently show a smaller white crescent oveall than CITE x NSHO do. This difference is from personal observation but it seems to hold up well in most individuals. BWTE x NSHO often show a very thin white "crescent" that appears as just a slightly curved white bar in some individuals while CITE x NSHO often show a thicker white crescent that covers more of the face. Compare the two individuals below, but as with all hybrids (and species to a lesser extent) there's plenty of variation.
Scapular Coloration The scapulars on both hybrids have black patterning, but the main color of those of BWTE x NSHO is a pale buffy coloration similar to the breast.
The main color of CITE x NSHO scapulars is a darker cinnamon, also similar to the breast. Compare Below.
Head Coloration The head coloration and iridescence of BWTE x NSHO tends to be slightly duller, grayer, and more in-line with BWTE. The head coloration and iridescence of CITE x NSHO tends to be brighter green and more in-line with NSHO. This feature doesn't seem entirely reliable, but it helps to give an impression of one or the other.
In January of 2019 I learned that this vole existed. A small Microtus completely isolated on a tiny Island west of Nantucket. I was compiling a list of species endemic to my home state of Massachusetts at the time, and was inquiring to my friend Skyler about a spider that was discovered on Nantucket. I told him about the list I was creating and he replied "U got muskeget vole right?" That was it. Those few words marked the start of my obsession. It is Massachusetts' only endemic vertebrate species and it was one that I had to see alive in person.
Muskeget is a unique island with a long and complicated history. I couldn't possibly squeeze it all into a journal post about the island's endemic vole but some background is important for those unfamiliar with Muskeget. The island is tiny, only about 240 acres, and it's completely uninhabited. One building exists on the island; a shack owned by Crocker Snow Jr. Aside from Crocker's shack there's what is left of an old duck blind, a pile of rubble that was once another shack, and a portion of land that one may be able to call an airstrip if you go back some years and squint hard enough. That is to say it's more or less untouched by humans. Fishermen and travelers occasionally wander the shores but unless someone is visiting for a specific purpose every once in a while, the island is empty. For those interested in learning more about the history of Muskeget and its vole this journal post discusses that aspect more in depth.
After learning about the vole from Skyler I began scouring the internet searching for any information I could find on it. Microtus breweri the Muskeget Vole, a small vole only known to occur on Muskeget Island, Massachusetts. At the time no photos of a living individual existed online (none that I could track down anyway) and the only photo of a living vole that I could find was a black and white photograph in Crocker Snow Jr.'s book about Muskeget. It became my mission to photograph this species and I would try to get out to Muskeget to search at any opportunity I could. I attended Tuckernuck Christmas Bird Counts and hoped that we might pop over to Muskeget for a few hours so I could search for the vole but that never ended up happening.
One day in September of 2020 my chance to visit Muskeget came. Skyler had found a rare Gray Heron on Tuckernuck Island and then relocated it on Muskeget Island. This was the first record for this species in the lower 48 states so naturally a small boat with some Nantucket birders was scheduled to go out the next morning. I was informed late that evening that Skyler had saved a spot for me on that boat, so if I could make it to Nantucket the next morning I would have a ride to Muskeget Island. Luckily I was able to make it down there in time for the boat. Unfortunately the Gray Heron had moved on and it was never seen in the area again. We got to spend some extra time on Muskeget and searched extensively for the voles. I even army-crawled under Crocker's cabin and flipped some boards hoping to find one, but to no avail. The Muskeget Vole continued to illude me. That trip was extremely special regardless of our failures to find the two targets of the day. I was finally able to experience Muskeget Island and now I was even more under its spell.
In the years following my trip to Muskeget I spent some more time on Tuckernuck and learned more about the Muskeget Vole. Apparently the last published sighting of one was in the 1990s. Beyond that, sightings were based on word of mouth with no photos or evidence that they were credible. We began to get worried that M. breweri was extinct. The only other terrestrial mammal on the island is Peromyscus so were people mistaking those for voles and claiming to have seen some while on Muskeget? In recent years the Great Black-backed Gull breeding population has increased on Muskeget, and tularemia and other tick-borne diseases have been reported nearby. Did these factors in combination with climate change and erosion of Muskeget do the voles in? Tularemia has been known to "burn through vole populations like wildfire" and it has been detected on Martha's Vineyard and Tuckernuck Island very recently. Had the Muskeget Vole silently gone extinct, alone on the island after thousands of years of trials and tribulations? Soon myself, Skyler Kardell, and Nick Tepper made it our goal to get out to Muskeget and do a general presence/absence survey of the voles. At the time we weren't sure if we would be declaring them extinct or documenting the few that we did find but it wasn't looking good.
The process of figuring this all out was long and complicated, but to make a long story short Skyler and I made our way to Harvard to discuss a trip out to Muskeget. We figured out our plan and learned that specimens of Muskeget Vole were obtained in 2015 but that work was unpublished, making the last confirmed sighting much more recent than we'd previously thought. Our hopes for seeing this species began to rise once again, and it seemed like my dream of photographing a Muskeget Vole may finally come true.
Nick Tepper applied for a permit to trap and collect (we would only collect if the population seemed high enough) M. breweri with myself and Skyler as subpermitees since Nick has the most experience with small mammal research. If we collected any the specimens would be donated to the Harvard collections for DNA work in the future. After some waiting we finally heard back from the Massachusetts Division of Fisheries and Wildlife in June of 2022. We got permission to trap and collect on Muskeget Island! I was on Tuckernuck with Skyler doing some research on Black-capped Chickadees when I found out and Nick was in Kansas doing breeding bird surveys. The next step was actually planning our trip to Muskeget now that all the permissions were in order, but first we all celebrated being granted permission to do this population assessment in the first place.
What happened next is hard to fit into a story about following my dream to search for a rare vole but it certainly can't be told otherwise. A few days after celebrating obtaining the permit with Nick he was in a major car accident and suffered a traumatic brain injury. The news obviously shocked me and others that know him, and it's something that I'm still processing. As of writing this Nick is on the long road to recovery.
Skyler and I decided to proceed without Nick for the time being. The permit expired at the end of 2022 and we knew he wouldn't be able to join us before then. Nick especially had worked so hard to obtain the permit and it felt like a disservice if we didn't use it, even if it would be without him.
Time passed and we continued planning our trip. Eventually we made it out to Muskeget in late August of 2022. We stayed on the island for 4 nights and the two of us extensively trapped all 4 corners of the island. We caught voles in all 4 areas and found enough to collect a few specimens for Harvard. Finally, my dream of nearly four years had come true, I'd seen and photographed the Muskeget Vole; Massachusetts' only endemic vertebrate. A lot of my time on Muskeget is a blur. It was filled with so many exciting moments including the voles and observing some amazing shorebird flocks in the lagoon, but it was extremely bittersweet. Nick should have been there. I wish he had been.
In Honor of Nick we will be doing a Birdathon to raise money for Assabet River National Wildlife Refuge. It's explained much better in the GoFundMe so please go read that. If you're able to I encourage you to donate. Nick is an amazing person and I wouldn't have had the opportunity to fulfill my dream of seeing the Muskeget Vole without him.
Posted on September 3, 2022 03:01 PM
by liliumtbn
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For such a small island, Tuckernuck has a disproportionately large number of mysteries. From the ghostly tales and warnings of the Yoho to the altogether unique song-type of the Black-capped Chickadees (Poecile atricapillus) found on Tuckernuck Island, there are countless stories and observations to get one searching for answers. My friend Skyler and I were on Tuckernuck researching the latter of the two aforementioned mysteries but stumbled across the answer, or perhaps part of the answer, to an entirely different mystery.
First of all some background is required. Part of this millipede mystery is why there are Giant Millipedes (Complex Narceus americanus) on Tuckernuck at all. The soil on the island is very sandy if you can even call most of it soil at all. The vegetation is very short due to the exposed nature of Tuckernuck, and the forest floor is mostly dry with leaf litter only where trees are most dense. This is noticeably different to the Giant Millipede's usual habitat of more humid old growth forest with extensive decomposing matter on the ground. The habitat on Tuckernuck just shouldn't support these millipedes from what is currently known about them, and it shows; Complex Narceus americanus has never been recorded on Cape Cod, Martha's Vineyard, or even Nantucket Island. They are completely isolated on Tuckernuck Island (Update: A population has been discovered on Coatue, Nantucket on June 17th, 2022). However, this isn't even the strangest part. Every spring and summer, countless millipedes are found headless along the trails and beaches of Tuckernuck Island. Some are further broken apart but the freshest ones are found only with their heads missing. This phenomenon occurring with Complex Narceus americanus has only been documented from a few places (including upstate New York) and has been a popular ecological mystery of Tuckernuck since at least the 1940s (Mckenna-Foster, Beaton, & Millman). American Giant Millipedes can release a harmful fluid that can cause burns (Wikipedia, 2022), so presumably the head is the only safe piece of the animal to consume. Clearly something on Tuckernuck has figured this out. A team funded by the Nantucket Biodiversity Initiative went to Tuckernuck in 2009 in an attempt to solve this mystery. They collected some very important data and information, but were not successful in finding the culprit to these decapitations. And that's how it stayed. A complete mystery. While many islanders and researchers had their theories about what was causing this phenomenon, no one was sure. Small mammals or birds were the main suggestions, and until June 7th, 2022, suggestions were all they were.
Skyler and I had planned to have 4 mornings of recording Black-capped Chickadee song on Tuckernuck Island, but days 3 and 4 were to be interrupted by winds, rain, and thunder sent North by a storm from the Bahamas. While it wouldn't technically be a tropical storm by the time the weather reached us, it was looking more and more like we wouldn't be able to record at all on our final 2 days. In the evening of day 2, we decided to try and get back onto Nantucket Island before the storm hit. We wanted to make sure we could get off Tuckernuck in time, and we wouldn't have been able to obtain any more recordings the next couple of days. Skyler attempted to call our ride off of Tuckernuck but to no avail, so he quickly began making his way to North Head to return a pot that needed to be returned before we left. Meanwhile our ride off island, Mark, tried calling Skyler. This was unsuccessful due to the poor signal on parts of the island, so Mark drove to the field station where we were staying. Eventually Skyler made his way back and I had packed up most of our stuff in order to leave as soon as possible, but there was still some of Skyler's belongings that he needed to pack before we hopped in Mark's truck and headed to the boat. Skyler climbed up to the loft and began packing up. After a couple minutes he looked out the small loft window and saw it; something was thrashing a millipede around beneath the bird feeders. That something was a Common Grackle (Quiscalus quiscula). He immediately yelled "Lily! Look out back a grackle is attacking a millipede!" While barely processing what he said, I ran to grab my camera and exited the field station in a rush of adrenaline. The door slammed behind me and all the birds flew off of the feeders, particularly a Common Grackle flew off of the ground and into a nearby shrub. I quickly tried snapping some photos but it flew slightly further back onto a higher branch. This is where I was finally able to obtain photographs. I watched as the grackle cleaned its bill by rubbing it against the branch, and a few drops of some type of liquid dripped off the end of its bill. Skyler followed me outside shortly after and we ran over to investigate the area on the ground where the grackle had been. We made our way over to the bird feeders and there it was, a sight Tuckernuckers are all too familiar with. Right on the ground beneath the feeders exactly where the grackle had been; one giant millipede but missing a very important feature: its head. The body was still wriggling slowly as Skyler picked it up, and the legs were moving as they often do for a while after the decapitations occur. With literally minutes to spare on Tuckernuck, we'd solved it, or so we thought. We loaded up the final bags and hopped in the back of Mark's pickup truck as he drove off towards his boat.
On our way back we began thinking. How could Common Grackles be the only culprit to these decapitations? Tuckernuck is a small island and the fauna is very different from the mainland. Common Grackles are present but not extremely abundant on island. Excepting large flyover migrant flocks, there typically isn't more than a few dozen grackles on Tuckernuck at a time. Would these be enough to account for the hundreds of headless millipedes that are scattered throughout the island every year? Since neither of us observed the grackle actively consuming a portion of the millipede, what if it was already decapitated and the grackle just tossed it around and then cleaned its bill after eating some nearby bird seed? While this explanation seems unlikely it can't be completely discounted as we didn't directly observe it consuming the head of the millipede. Why is this phenomenon limited to a few specific locations involving this millipede complex? Is the benefit that great for grackles to be eating just a tiny portion of each animal? It also still remains to be seen why the millipedes are so hyper-abundant on Tuckernuck in the first place. Could these millipedes represent a unique species? Perhaps DNA testing could help to understand this aspect. And if it's not just grackles, what other species are decapitating the millipedes of Tuckernuck Island? Our findings add a large piece to this puzzle, but don't completely solve all aspects of the millipede mystery of Tuckernuck Island. Maybe Tuckernuck will hold on to this mystery for as long as it can, as it tends to do. Maybe we'll never know the full picture. But the allure is in the questions and mysteries, and that's part of what makes this island so special.
Until next time, Tuckernuck.
Citations: Mckenna-Foster, A., Beaton, C., Millman, L. (2009). An Investigation into headless millipedes on Tuckernuck Island, MA.
1856 - July: Specimens collected by Dr. T. M. Brewer In July of 1856 six specimens were collected from Muskeget Island by Dr. T. M. Brewer (Lyon & Osgood, 1909). This is the earliest report I could find of Microtus breweri and seems to be the first documented occurrence of this species.
1857: First description of Microtus breweri In 1857 was described by Spencer Fullerton Baird as "Gray Mouse (Arvicola breweri)" on page 525 of volume 8 of Reports of explorations and surveys, to ascertain the most practicable and economical route for a railroad from the Mississippi River to the Pacific Ocean. (Department., U. S. W., 1857). There are several resources online that list the original description of this species as being from 1858, but I can find nothing that supports this, and the original description is clearly dated as 1857.
~1885-1888: The Muskeget Life Saving Station burns It's very unclear when the fire in the Muskeget Life Saving Station happened but from what I can find it should be anywhere from 1885 to 1888, give or take. The fire happened "a few years before" 1890-1891 (Miller, 1896). This is said to be the cause of the introduction of cats to Muskeget. Supposedly this fire allowed them to escape onto the island and decimate the population of M. breweri. A few secondary sources seem to claim that the fire happened in 1894 but this doesn't line up with Miller (1896).
1887- June 1890: South Point Island At some point between 1887 and June 1890, South Point was disconnected from Muskeget Island to form South Point Island due to the shifting sands and ocean currents. South Point went from the shape of the dotted lines in the image at the top of this page to the island labeled as "SOUTH PT ID." When the US coastguard surveyed Muskeget in 1887 South Point was still connected to Muskeget. We know that South Point Island was no longer connected by June 25th of 1890 due to a letter written from F. H. Kennard to Gerrit S. Miller describing his and Dr. C. S. Francis' visit to Muskeget from June 25th-29th of 1890. In this letter, Kennard refers to South Point as "South Point Id." and Muskeget as "Muskeget proper." A population of M. breweri remained on South Point and Adams Islands, but were apparently never present on Gravelly Island (Miller, 1896).
Jun 25-29, 1890: The "last" sighting On June 25th-29th F. H. Kennard and Dr. C. S. Francis visited Muskeget Island and reported seeing M. breweri on the island. "While we saw numbers of them on South Point Id., we did see a very few in the middle of Muskeget... We noticed and marked the difference in the number of mice on South Point Island and on Muskeget and laid it to the cats," (Miller, 1896).
Jun 30, 1890-1891: Extirpation from Muskeget Proper John R. Sandsbury, the island caretaker at the time, reported that M. breweri disappeared from Muskeget Island some time from 1890-1891. The sighting from June 1890 was the last reported sighting of the species on Muskeget proper at this time (Miller, 1896).
Jul, 1892: M. breweri confirmed to be absent from Muskeget Island In July of 1892 a careful search of Muskeget was conducted and no trace of M. breweri was found on the island. At the same time, South Point and Adams Islands were reported to have thriving colonies of this species (Miller, 1896).
Dec 28, 1892: Declining on Adams Island On December 28th, 1892 Miller visited the islands and reported that M. breweri was "...as numerous as before on South Point Island, but the colony on Adams Island had greatly diminished," (Miller, 1896).
Jun 21, 1893: Extirpation from Adams Island and re-introduction to Muskeget proper In June of 1893 Gerrit S. Miller, Outram Bangs, and Chas F. Batchelder visited Muskeget. "We found that the Microtus colony on Adams Island had entirely disappeared. On South Point Island, however, the mice were so abundant that in less than two hours we caught forty-three. After selecting as many as we wanted for specimens, we turned out twenty-six on Muskeget," (Miller, 1896). At some point prior to the re-introduction of M. breweri to Muskeget, cats were extirpated from the island. I'm not able to find a date for this.
"Of the forty-three taken on June 21, 1893, no less than nineteen were slightly albinistic. Each of these abnormal individuals showed a distinct white patch or tuft on the median line of the head just back of the eyes. Only one specimen was marked with white elsewhere on the body. In this case was a broad white stripe beginning on the lower lip and passing back under the chin and throat. It is a significant fact that in every instance the abnormal color marks were in the median line, and moreover that they occupied regions which in many mammals are normally marked with white," (Miller, 1896).
Jul, 1895: Extirpation from South Point Island and increasing population on Muskeget Island "... Mr. W. K. Fisher collected two dozen specimens for the U. S. Department of Agriculture during July, 1895. Mr. Fisher found two colonies - both in clumps of beach plum bushes - one at the east end of the island, near the place where we liberated the mice in 1893, the other about a mile farther west. He also found that the species was extinct on South Point Island," (Miller, 1896).
Present Day Nowadays the Muskeget Vole sits alone on Muskeget Island. South Point, Adams, and Gravelly Islands no longer exist. Thankfully the shifting tides that washed away these islands were the very reason that M. breweri was saved from extinction in the first place. Apparently many individuals on Muskeget still show a white blaze on their forehead, though I can't find evidence for this at the moment. If these individuals do exist though, they're an incredible reminder of this species' long and complicated history on an ever-changing island.
Literature Cited:
Department., U. S. W., Baird, Spencer Fullerton, Baird, Spencer Fullerton, Henry, Joseph, Ford, Thomas H., of Engineers., U. S. A. C., … T. Sinclair’s Lith. (1857). Reports of explorations and surveys, to ascertain the most practicable and economical route for a railroad from the Mississippi River to the Pacific Ocean (σ. 906). Ανακτήθηκε από https://www.biodiversitylibrary.org/item/268867
Early Thursday morning Max, Michael, and I headed down to Hyannis to board the earliest ferry to Nantucket. We tried birding on the ferry, but didn't get too much apart from the occasional jellyfish in the water, although the boat was moving too fast to photograph them. When we reached land, we were greeted by Skyler and Will. Those of us who hadn't met previously shook hands and started to get to know each other. Old friends picked up where they left off.
Eventually we headed out of town towards the West side of the Island. En route to Jackson Point, we talked and listened to songs from countless different musicals, everyone just happy to be in the company of each other. When we arrived at Jackson Point, there wasn't much in terms of Passerines, so we headed out to Esther Island. There were some decent species of shorebird including Whimbrel and Western Willet. A Peregrine was also flying around looking for a meal. Some Tiger Beetles scurried along the beaches as we walked further along the island. Huge numbers of Black Tern flew around and rested on the flats. Sanderlings, Semipalmated Plovers, Piping Plovers, and other shorebirds added to the numbers. Later on, we got to the ocean-side of the beach. The waves were bigger there and a thick layer of fog could be seen. Soon after we arrived on the ocean-side, Michael shouted out "Cliff Swallows!" We all looked as quickly as possible and could spot 5 individuals darting off into the fog. I quickly snapped a photo of the last one before it too, was consumed by the fog. We rested for a few minutes near the roaring waves, and waded in a bit, enjoying the cool water as it rushed in and out.
After Esther Island, we headed North to Eel Point. There wasn't too many species of note at this location apart from the Jellies that we had to watch out for while wading through the water. On our way back to the car, the sand was extremely hot and burned our feet. There was no alternative route, so our only option was to fight through it, because it was too far to run the entire way.
A few minor stops later and we had made it to the Serengeti. Although quite far away from its African counterpart, Nantucket's "Serengeti" greatly resembles the landscape of the African Savannah, hence how it got its name. Apparently in the 1800s, the Serengeti was more or less a shortgrass prairie. It's very different in the present, with the ground covered in scrub oak and trees dotted around the area. This prairie-like habitat was perfect for Eskimo Curlew and, unfortunately, Eskimo Curlew were perfect for hunters...
We checked a large area of the Serengeti thoroughly in an attempt to locate Ring-necked Pheasants, but only found a couple of Merlin. After walking through brush for an hour and a half, we decided to take a break at Skyler's house for a while.
It was getting late in the afternoon, so we decided to head for Milestone Cranberry Bogs. We searched for rails and anything else we could find, but to no avail. In the middle of the cranberry bogs, we talked and just had a wholesome hour or so watching the sun set together. On our walk back to the car, the calls of Helmeted Guineafowl echoed through the bog.
We got into the car and headed to a few pull-offs to listen for Barn Owl. We didn't end up hearing any, but at our last stop the sky was in clear view, and with our windows open I could look straight up at the stars. Due to light-pollution and/or a cloudy sky at most places I'd been throughout my life, I'd never payed much attention to the stars, and never got a good view. That is, until that evening. Thousands and thousands of bright stars dotted the sky, thicker in some areas than others. Something about them attracted my gaze, and I just couldn't pull my eyes away. I was staring straight up at the sky, but I was perfectly content, more content than I can ever remember being. I had just spent the day exploring this beautiful island with some amazing people, and now we were sitting in what seemed like perfect silence on the side of a road. It felt like an eternity that I stared up at those stars, but I wanted to remember that moment. It was the perfect evening to a perfect day at the end of the summer, and I didn't want to forget a second of it.
We got back to Skyler's house soon after that last stop. We said goodbye to Will since Skyler would be driving him back to where his family was staying on the island. For some reason it felt like I wouldn't see Will again, even though we'd just met that morning, and I'm sure our paths will cross again at some point. It was a bit sad because I knew our time on Nantucket was ending, and we'd be leaving early the next morning, but I was still extremely content with our time there, and happy to spend it with friends. Skyler drove Will home and Michael, Max, and I went to bed. I didn't sleep well that night but it didn't matter, as I still felt that strange indescribable tranquility.
In the morning, Skyler saw us off at the ferry. And again, for some reason, it felt like I wouldn't see him again, even though we'd definitely go birding together in the future. As the boat drove off, I stared back at Nantucket, happy to be going home, but sad to be leaving it behind. Eventually, the island disappeared into the distance, but I'm sure I'd be seeing it again soon.
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