Newly Discovered Population of Eastern Musk Turtle at Round Lake

Posted by Mark A. Conboy and Sarah M. Larocque

The provincially and nationally threatened stinkpot (Sternotherus odoratus) is common at QUBS, making our population an essential one when it comes to conserving and researching this species. Photo: Mark A. Conboy.

The eastern musk turtle (Sternotherus odoratus), otherwise known as the stinkpot, is a provincially and nationally threatened species. Despite being quite rare throughout most of Ontario, research (summarized in a previous post) suggests that in Lake Opinicon stinkpots may be almost as numerous as the more familiar painted turtle (Chrysemys picta). Occasionally a stinkpot is seen in one of the large lakes adjoining Lake Opinicon, but until recently there were no known occurrences of this species in the QUBS Back Lakes. On August 20, 2011 while sampling fish, we found a hitherto undocumented population of stinkpots in Round Lake. We captured five males and four females among three unbaited fyke nets set in the littoral zone of the lake.

Stinkpots normally inhabit water that is less than 2 m deep, so the presence of stinkpots in Round Lake is somewhat surprising because shallow water habitat is relatively limited. Round Lake is the deepest lake at QUBS (mean depth = 12.6 m; maximum depth = 30.1 m). The shallow littoral zone is confined to two narrow bands in the Lake’s north and south ends. According to recently completed bathymetry measurements, only 6.7 % of Round Lake’s total surface area contains water that is 2 m or shallower. When considering depth alone, it seems that Round Lake is not ideal for stinkpots. However, the limited littoral zone that does exist seems like perfect habitat for a number of reasons: (1) Potential prey species abound; Round Lake hosts the most diverse fish community of any QUBS Back Lake yet surveyed (with 13 species). It should be noted that aquatic invertebrates, rather than fish, tend to comprise most of the stinkpot’s diet. Even if fish represent a small fraction of the stinkpot’s diet, the fish diversity is indicative of a generally healthy and productive ecosystem that includes lots of invertebrates. (2) The shallow bays are heavily vegetated and contain plenty of submerged woody debris for shelter and foraging opportunities. (3) The wetland at the south end of the lake contains potential nesting sites, such as muskrat (Ondatra zibethicus) lodges.

This coming summer we plan to look for stinkpots in Garter Lake which connects to Round Lake by a broad marshy channel. We expect to find them there. In addition to the obvious conservation importance of the Round Lake stinkpot population, there is the potential for future research opportunities. For example researchers will be able to compare the diet and heavy metal concentration in stinkpots and their prey between sites invaded by zebra mussels (such as Lake Opinicon) and non-invaded sites (such as Round Lake). Researchers can then determine whether or not zebra mussels are an important pathway for the transfer of mercury in stinkpots. Of course, high loads of heavy metals such as mercury can have all kinds of negative impacts on turtles so studies such as the one described above can be important in developing essential knowledge when planning a conservation strategy for this threatened species.

Crayfish in the back lakes.

Posted by Sarah M. Larocque and Mark A. Conboy

Figure 1. A) Dorsal and B) ventral view of a calico crayfish (Orconectes immunis) found in Lindsey Lake.

In a recent blog post (November 11), we reported our results of the small fish community survey undertaken in the QUBS back lakes and wetlands this summer. In addition to gathering information on fish, we took advantage of our time on the water to sample crayfish diversity at each water body. We captured crayfish using baited minnow traps and seine nets as outlined in the fish post. In this post we also included crayfish data from Lake Opinicon (which we did not sample in the fish survey). Specimens from Lake Opinicon were caught using minnow traps, seine nets and by hand. Crayfish are yet another group of organisms that have received virtually no attention at QUBS; we present the first (preliminary) summary of crayfish diversity and distribution for the station.

Understanding the diversity and distribution of crayfish at QUBS is important for three reasons. First, we would like to provide distributional information to future crayfish researchers who may be looking for study populations. Second, we want to compare contemporary species distribution to future sampling results in order to understand the changes that take place in lake and wetland ecology over time. Finally, crayfish, though often abundant in healthy ecosystems can quickly become imperiled through pollution and the introduction of invasive species. Crayfish are the largest mobile invertebrates in Ontario, and play an important role as scavengers, predators and prey in our aquatic ecosystems. We want to be able to monitor the health of QUBS’s crayfish populations to ensure their continued vitality and the vitality of our aquatic ecosystems at large.

Worldwide there are more than 540 species of crayfish (also called crawfish or crawdads). Crayfish diversity in Canada is low with only 11 species, all of which, except for the Signal Crayfish (Pacifastacus leniusculus), are found in Ontario. The centre of crayfish diversity in the province is southwestern Ontario, but at least five native and two introduced species of crayfish may be found at or near QUBS. Our sampling turned up four species:

• Virile Crayfish (Orconectes virilis) –  Very common in Lake Opinicon and Warner Lake
• Calico Crayfish (O. immunis) – Fairly common in Lake Opinicon, Warner Lake, Round Lake, Lindsey Lake, Cold Springs Pond and Lower Poole Pond. Abundant in the Dowsley Ponds.
• Northern Clearwater Crayfish (O. propinquus) – Appears to be fairly common at Chaffey’s Lock and other locations in Lake Opinicon. Found in some wetlands along Cataraqui Trail. Not yet recorded in the back lakes.
• Common Crayfish (Cambarus bartonii) – One collected at Warner Lake; first record for this species at QUBS. Could also be found in streams but has not been to date.

An additional native species reaches eastern Ontario but it prefers large rivers, a habitat type which is lacking at QUBS, so it is unlikely to be found at the station. Fortunately, no invasive crayfish species have been found at QUBS. There are two invasive species of concern in eastern Ontario Rusty Crayfish (O. rusticus) and Allegheny Crayfish (O. obscurus). The spread of these invasive crayfish is due in large part to transportation from their native ranges to other watersheds by anglers who use them as bait. The introduction of the Rusty Crayfish in Ontario took place in 1960’s when it was brought here for use as bait by a non-resident angler. To help stop the spread of invasive crayfish it is currently illegal in Ontario to transport crayfish (dead or alive) to water bodies other than where it was caught. Also, if you think you caught an invasive crayfish, you are supposed to kill it and report the observation to the Ministry of Natural Resources. However, it is important to identify crayfish correctly before killing them. An excellent visual guide to all of Ontario’s crayfishes can be found here.

Some native crayfish (e.g., Northern Clearwater) are in decline due to competition for food and shelter from the dominant and more aggressive Rusty Crayfish. Recently an article published in Fisheries (Lieb et al. 2011) explores various management strategies to prevent the spread of invasive crayfish spread and conserve threatened native crayfishes in North America. Restrictions on transport of bait and education can be effective tools to prevent the further spread of invasive species but once non-native crayfish become established it can be almost impossible to remove them. As we expand our sampling of lakes and wetlands at QUBS this coming summer we’ll continue to document the native and non-native crayfish and work towards monitoring our local water bodies for the first signs of invasion by invasive species so that we can act quickly to ensure the integrity of our native crayfish diversity.

References
Lieb DA, Bouchard RW, Carline RF, Nuttall TR, Wallace JR, Burkholder CL. 2011. Conservation and management of crayfishes: Lessons from Pennsylvania. Fisheries 36: 489-507

Figure 1. A) Dorsal and B) ventral view of a calico crayfish (Orconectes immunis) found in Lindsey Lake.

Opinicon’s Own Lichen

Posted by Mark Conboy

A cliff-face lichen community on Snake Island, Lake Opinicon. Two clusters of Lecanora opiniconensis (A) on either side of some scattered rock-posy (Rhizoplaca subdiscrepans).

Among the least studied organisms at Queen’s University Biological Station are the lichens. That’s not to say that no one has bothered to look at them; in fact the discovery of a new species of lichen led to it being named after Lake Opinicon. Lecanora opiniconensis was first discovered and named by eminent lichenologist Irwin Brodo while he was visiting the station as a guest lecturer during a population ecology field course in the 1980’s. Brodo told me that when he first discovered this species on Snake Island (in Lake Opinicon) he thought it was an Ontario endemic. He has subsequently found it in the Adirondacks and northern Manitoba. Other workers have found it in the southwestern United States. It’s a small species with apothecia (fruiting bodies) that are only a few millimetres across. It could easily be missed among the colonies of the more abundant and superficially similar scattered rock-posy (Rhizoplaca subdiscrepans). Compared to R. subdiscrepans, the thallus of L. opiniconensis is darker green and the apothecia are non-pruniose. As far I know this lichen is the only organism that has been named after Lake Opinicon.

Small fish communities on the back lakes and marshes of QUBS

by Sarah. M. Larocque and Mark A. Conboy

Figure 1. Central mudminnow (Umbra limi) seined from Round Lake.

Throughout July and August, 2011, we conducted a preliminary fish survey of selected lakes and wetlands at QUBS. Our goal was to begin assembling a comprehensive understanding of the distribution of fish species in the major water bodies within the boundaries of QUBS properties. Although the distribution of some fish is well known at QUBS due to past and present research (e.g. northern pike [Esox lucius], sunfish [Lepomis sp.] and largemouth bass [Micropterus salmoides]) as well as recreational angling, our understanding of the distribution of many small fish species (e.g. shiners, minnows, daces [family Cyprinidae]) is very limited.

We surveyed fish communities at QUBS for two major reasons. First, we wanted to document the ichthyofauna at the station to provide baseline data on distribution for future fish researchers who may be looking for study populations in specific habitats. Second, we wanted to be able to compare contemporary species distribution to historic and eventually future records which will help elucidate the ways in which the lake and wetland ecology changes over time.

Our fishing efforts primarily focused on the perimeter of water bodies. We sampled along shorelines in as many types of habitats as possible within each lake or wetland (e.g. among emergent vegetation, logs and weed beds). The sampling techniques we employed were: cat food-baited minnow traps, fyke nets (no bait), and seining. The various trapping techniques produced differing levels of success: minnow traps were largely unsuccessful, fyke nets excelled at capturing larger species, and seining was the most proficient at capturing smaller species. As this was a preliminary survey, we did not standardize our trapping techniques across each of the water bodies, so the relative numbers of captured individuals for each species are not comparable among the different lakes. Here we report only presence/absence data for each of the water bodies surveyed. We also give a brief overview of the geography of each of the surveyed lakes and any known history of research and stocking.

Warner Lake (Mean depth = 2.9 m; Maximum depth = 6.4 m; Surface area = 9.2 ha)

Unlike most lakes at QUBS, no surface water tributaries flow into Warner, instead the lake is replenished by precipitation run off and an underground spring near the lake’s northwest shore. The only outflow from Warner is through a shallow creek that disappears into the bedrock less than 100 m from the lake. In effect Warner is a closed system and it is thought that any fish present in the lake have been introduced. Around the 1950’s and 60’s, Warner Lake was likely stocked with largemouth bass, possibly among other species, by local cottagers (Phelan, pers. comm.). Continued maintenance of the lake’s current water levels relies on the integrity of a beaver dam.

The lack of above ground inflows and outflows means that migration of bass and other species to and from the lake is impeded and as such Warner Lake has been an optimal environment for extensive studies on the stocked largemouth bass. Over the past two decades various research projects have occurred, from nest surveys to the use of an extensive hydrophone acoustic telemetry array to monitor three-dimensional movements and behaviours of bass throughout all seasons. In recent years the hydrophone array has suffered from damage by muskrats (Ondatra zibethicus) and technical malfunctions, and is currently not in use. At least one major winter kill has been documented, resulting in the death of most of the lake’s bass. The bass were subsequently restocked. The current largemouth bass population is self-sustaining with untagged adults and young of year (YOY) as well as older fish from past telemetry studies.

Fish diversity is relatively low in Warner Lake with only five species. In addition to largemouth bass, we also captured pumpkinseed (Lepomis gibbosus), yellow perch (Perca flavescens), yellow bullhead (Ameiurus natalis) and brown bullhead (A. nebulosus). In a beaver pond ephemerally linked to Warner Lake we captured a stunning 1422 brown bullhead with approximately 97% being YOY in one fyke net. By comparison, we captured only three brown bullheads in the entire main lake.

Lindsay Lake (Mean depth = 4.4 m; Maximum depth = 10.9 m; Surface area = 31.5 ha)
Poole Lake (Mean depth = 2.6 m; Maximum depth = 6.5 m; Surface area = 24.2 ha)

Although traditionally considered separate lakes by QUBS researchers, the main basins of Lindsay and Poole are broadly connected through a shallow area of dead standing timber and aquatic vegetation. There is no real barrier to fish movement between the two basins so we treat these lakes together here. Other small wetlands fill some of the bays, particularly on Lindsay Lake and there are a variety of inflows and out flows. Like Warner Lake, Lindsay and Poole have had long term studies and surveys of their largemouth bass populations. In addition there has been work on pumpkinseed and population monitoring of northern pike through pit tagging. These lakes were likely stocked with game fish and feeder fish by cottagers decades ago.

We found nine species, eight of which were common to both lakes. Only banded killifish (Fundulus diaphanous) was captured in Poole Lake and not Lindsay. The species common to both lakes were northern pike, largemouth bass, pumpkinseed, bluegill (Lepomis macrochirus), rock bass (Ambloplites rupestris), yellow perch, yellow bullhead and brown bullhead.

Long Lake (Mean depth = 6.8 m; Maximum depth = 26 m; Surface area = 15.5 ha)

Long Lake is rather deep for most of its length, with a sudden drop off close to shore which results in a narrow littoral zone in the northern half of the lake. The southern half of Long Lake is very shallow and the bottom is covered in sand and marl-like deposits. There is only one inflow to Long, and that is an intermittent stream which flows from a small pond situated on the ridge east of the lake. There are no major wetlands on the shores of Long Lake. The lake has also been subject to studies of its largemouth bass and bluegill, and was probably stocked.

In Long Lake we found bluntnose minnow (Pimephales notatus), largemouth bass, bluegill, rock bass and yellow perch. Because of the limited littoral zone, we had limited seining opportunities at the north end of the lake. We suspect there are potentially other species of minnow and shiner in the lake that additional seining could reveal.

Round Lake (Mean depth = 12.6m; Maximum depth = 30.1 m; Surface area = 15.0 ha)

Round Lake is the deepest lake at QUBS. It is connected to Garter Lake by a wetland and probably shares much of its ichthyofauna. We did not survey Garter Lake in 2011, but plan to do so next year. The two tributaries of Round Lake are small creeks flowing east from a complex of wetlands along the Cataraqui Trail. Round Lake too has a history of bass and pumpkinseed research and was also probably stocked. There is also ongoing research using mesocosms to test theoretical predictions using populations and communities of Daphnia under natural variation in light and temperature.
Of the water bodies yet sampled Round Lake boasts the most diversity of fish species with 13. We captured bluntnose minnow, blackchin shiner (Notropis heterodon), blacknose shiner (N. heterolepis), banded killifish, northern pike, central mudminnow (Umbra limi; Figure 1), largemouth bass, pumpkinseed, bluegill, rock bass, yellow perch, yellow bullhead and brown bullhead.

Elbow Lake (Mean depth = 3.7 m; Maximum depth = 10.6 m; Surface area = 26.0 ha)

Elbow Lake is located on a property that QUBS manages in partnership with the Nature Conservancy of Canada (NCC). The property was once a retreat for employees of the Hewlitt-Packard computer company. It now hosts a five week long summer day camp, the QUBS Eco-Adventure Camp. This lake has had a longer history of recreational use (fishing and otherwise) than the previously mentioned lakes. Hewlett-Packard had a strict catch and release policy for bass fishing; presently QUBS and the NCC do not allow any harvest of any fish species. Among QUBS lakes (aside from Opinicon and the other Rideau Lakes which boarder our properties), Elbow is unique in that it is the only one whose water level is controlled by a man-made dam. Elbow is connected to Spectacle Lake through a shallow wetland and probably shares most if not all of the same fish species but we have yet to thoroughly sample Spectacle Lake. Elbow Lake has been subject to very little research, though some largemouth bass have been fitted with pit tags. The stocking history of this lake is unknown.

In addition to largemouth bass we found banded killifish, black crappie (Pomoxis nigromaculatus), pumpkinseed and yellow perch.

Wetlands
We sampled a variety of beaver ponds and marshes mainly by seining but occasionally also by deploying minnow traps. All of these wetlands contained northern redbelly dace (Chrosomus eos), whereas the lakes did not. Other species that we captured in wetlands but not in the lakes included brook stickleback (Culaea inconstans) at Barb’s Marsh and Iowa darter (Etheostoma exile) at Lower Poole Pond. On the other hand, all the lakes contained largemouth bass and yellow perch while the wetlands did not. See Table 1 for a complete list of species found in each wetland and lake.
One wetland in particular, Lower Poole Pond (sometimes labeled as Beaver Marsh on QUBS maps) was sampled 21 years ago. Though we did not follow the protocol used by Keast and Fox (1990), our results are interesting to compare to theirs, despite the differences in methodology and the comparatively limited nature of our sampling in Lower Poole Pond. We found blackchin shiner, blacknose shiner, bluntnose minnow, northern redbelly dace, banded killifish, Iowa darter, and pumpkinseed. In 1990, Keast and Fox found those species plus fathead minnow (Pimephales promelas), golden shiner (Notemigonus crysoleucas), central mudminnow, brown bullhead, yellow perch and brook stickleback. Since Keast and Fox (1990), the beaver dam at the south end of Lower Poole Pond has broken and water levels have dropped significantly, and may have influenced the fish composition in the pond. We have yet to find fathead minnow or golden shiner in the QUBS back lakes, but both species do occur in Lake Opinicon.

Future Surveys

We now have good survey data for ten water bodies contained within the QUBS properties. We also have extensive records of fish presence/absence for Lake Opinicon (about 30 species) which we do not treat here. This data will soon be provided in an updated QUBS fish species list which can be found at: http://www.queensu.ca/qubs/resources/specieslists.html. When we recommence surveys next summer we will attempt to standardize the sampling techniques between water bodies, resample some lakes and wetlands that we felt were undersampled (e.g. Lower Poole Pond) in 2011 and extend the sampling to additional water bodies at QUBS. Also, sampling Lake Opinicon would provide an excellent data set to compare to the works of the late Allen Keast who worked on the lake extensively before the introduction of Dreissena mussels. We could look at how fish communities and fish diets have changed since the catastrophic habitat change brought on by the invasive mollusks. We are getting closer to our goal of obtaining a complete picture of the fish communities at QUBS, but there is still much work to be done.

Literature cited
Keast A, Fox MG. 1990, Fish community structure, spatial distribution and feeding ecology in a breaver pond. Environmental Biology of Fishes 27:201-214.

Table 1. Fishes encountered when sampling aquatic bodies on QUBS property (X indicates present; H indicates historically found). Click on image for larger version.

Two recent bee publications.

I subscribe to a number of listservs and on occasion am sent information on new publications that might be of general interest. One of these is a joint publication of the United States Department of Agriculture and the Pollination Partnership, a not for profit head-quartered in San Francisco entitled “Bee Basics An Introduction to Our Native Bees“. It provides a very nice and eminently readable consideration of the ecology, anatomy and diversity of bees of the United States, many species of which of course are also common to Canada. The publication even alludes to the pollination parkthat has been created on an abandoned landfill cite near the City of Guelph.

The second publication is a very well received book from bee biologist Laurence Packer of York University in Toronto. It is a finalist for the Lane Anderson Award which honours two Canadian-authored science books annually. Laurence talks with erudition, first hand knowledge and humour about bee biology, the role of bees in ecosystems, and their recent decline.

Rise of the Red-bellied Woodpecker

Posted by Mark Andrew Conboy

Male Red-bellied Woodpecker (Melanerpes carolinus). Source KenThomas.us

Numerous species of birds in Ontario have expanded their ranges further north in during the past century. For example, the Turkey Vulture (Cathartes aura) has dramatically extended its range throughout Southern Ontario beginning in the early 1900’s, when it was rare in most of the province but is today a common species north into parts of Central Ontario. Mourning Dove (Zenaida macroura), Northern Cardinal (Cardinalis cardinalis), Orchard Oriole (Icterus spurius) and perhaps even Cerulean Warbler (Dendroica cerulea) have all undergone similar range expansions (Cadman et al 2007). In recent decades this pattern has continued with the Red-bellied Woodpecker (Melanerpes carolinus), which is now being sighted with increasing frequency in Eastern Ontario.

Red-bellied Woodpeckers have always been considered fairly rare at QUBS so their apparent sudden increase in the area is of considerable interest. I have been recording occurrences of this species on our properties since 2008. I summarize those observations below:

2008
1 on the Moores Tract
2 at the southeast corner of Hughson Tract (copulation reported by Frank Phelan)
1 at Lindsay Lake Road

2009
1 at the Southeast corner of Hughson Tract
1 on Lindsay Lake Road

2010
2 in Silver Maple Swamp

2011 (to date)
1 north of Warner Lake
1 at QUBS Point (visited bird feeders at Ironwood Cottage)
1 on Old Bedford Road
1 on Lindsay Lake Road
2 at the Dowsley Ponds

Additional sightings from the QUBS area reported on eBird (http://ebird.org/content/ebird/) by other observers are: 1 at “QUBS” in 2008 (Martin Piorkowski); 1 at Bedford Mills in 2010 (Peter Blancher); 1 at the cemetery on Opinicon Road (Patrick Blake) and 1 in Elgin (North Leeds Birders), both in 2011. So far the only breeding evidence we have is a pair observed copulating on the Hughson Tract in 2008 (Phelan, personal communication). Observations of Red-bellied Woodpeckers from other parts of Eastern Ontario include occasional eBird reports from Charleston Lake (to the south of QUBS) are starting in 2005 and the Ottawa area (to the north) starting in 2009.

Why Red-bellied Woodpeckers are now expanding into Eastern Ontario with success at this time is unclear. Possible explanations include changing climate contributing to increased winter survival; additional foraging opportunities resulting from bird feeders; and maturation of second-growth forests providing appropriate breeding habitat. The most recent edition of the Atlas of the Breeding Birds of Ontario 2001-2005 showed that 15 species expanded their range edge northward in Ontario in the 20 years since the first edition of the atlas. The northward expansion of most of these species may be attributable to any or all of the aforementioned hypotheses for the Red-bellied Woodpecker.

The threatened (yet potentially plentiful) eastern musk turtle

Posted by Sarah Larocque

Few have seen the eastern musk turtle (Sternotherus odoratus), more commonly known as the stinkpot turtle. This might seem logical because of its current status as a threatened species both provincially and nationally. Perhaps just as likely is the possibility that this turtle goes relatively unnoticed because of its small size and highly aquatic lifestyle.

With a carapace length of up to 137 mm, the stinkpot is one of North America’s smallest turtles, inhabiting shallow water bodies with muddy bottoms. Stinkpots crawl along the bottom and probe in the mud, sand, and vegetation for food of almost any type. Being bimodal breathers (able to exchange gas in both air and water), stinkpots remain submerged for long periods of time. As a result, the stinkpot often has algae growth on its shell, further camouflaging it from human eyes. Instead of basking out of water, stinkpots bask at the water’s surface with their carapace exposed or floating in among aquatic vegetation, and thereby go unnoticed unlike typical basking turtles.

Rarely leaving the water’s edge, stinkpots are hard to detect, let alone quantify their population size. Fortunately, my work involving hoop nets allowed me to come across the stinkpot on numerous occasions. For example, from my spring sampling of 105 net sets in 2010, we captured 111 stinkpots (74 males; 37 females). In comparison, we only captured 101 painted turtles (Chrysemys picta; 67 males; 34 females), a species that appears quite common. Similarly, in fall with 60 net sets, we captured 48 stinkpots (45 males; 3 females) which was nearly twice as many as the 26 painted turtles (21 males; 5 females).

Lake Opinicon is known to have healthy turtle populations; however, it is surprising to find that a threatened turtle like the stinkpot has higher catch rates than the commonly found painted turtle. There have also been reports of large numbers of stinkpots in nearby Lower Beverly Lake. For a threatened species, this is good news. Unfortunately, we only have number of captures and neither the actual population size nor data on whether populations are increasing/decreasing/status quo.

The stinkpots threatened status is in part from attributable to such factors as shoreline development and boat collisions.  Yet perhaps in part its status is due to it being difficult to detect … maybe these small critters are more plentiful than once thought (at least in Lake Opinicon)!

20 Years of Red-shouldered Hawk Surveys on Opinicon Road

Posted by Mark Andrew Conboy

Red-shoulder Hawk. By gerry from USA (Flickr) [CC-BY-2.0 (www.creativecommons.org/licenses/by/2.0).

 

Any day now the skies over Eastern Ontario will begin to ring with the calls of Red-shouldered Hawks (Buteo lineaus). This vocal hawk is one of the most commonly encountered raptors on the Frontenac Arch. It’s also one of the few forest raptors that have been subject to long term monitoring in Eastern Ontario. Beginning in 1991 the Red-shouldered Hawk and Spring Woodpecker Survey has been conducted each year along Opinicon Road in an effort to keep track of Red-shouldered Hawk numbers. In this post I summarize the results of 20 years of counting Red-shouldered Hawks along Opinicon Road. The counts were completed by Ron Weir and others. Thanks to Ron for providing me with the survey data.

The results of the Red-shouldered Hawk surveys show that there has been a significant increase in Red-shouldered Hawk numbers since 1991 (P=0.0013). The lowest count was 5 birds in 1992. The highest count was 27 birds in 2003. The mean count is 17.05 birds. Red-shouldered Hawk numbers across their Ontario range appear to be steady or increasing and the data from Opinicon Road matches this trend.

QUBS is situated in what is currently the heart Red-shouldered Hawk abundance in the province (Cadman et al 2007). The largely intact forests that cover our part of the Frontenac Arch provide habitat for these sylvan raptors and are likely the reason for the high numbers recorded here. Red-shouldered Hawks may have been far more abundant than they are today all across Ontario prior to the conversion of forests to farmlands (Weir 2008). The species continued to decline in the mid 1900’s. In 1983 the Red-shouldered Hawk was designated a species of concern in Canada, due to the large declines in populations associated with forest clearing. In 2006 it was reclassified as not at risk. Today the most commonly observed hawk in the region is the Red-tailed Hawk (B. jamaicensis). It prefers large tracts of farmland or other open terrain. It has probably replaced the Red-shouldered Hawk throughout much of southern Ontario as a direct result of habitat alteration. However, at QUBS Red-shouldered Hawks remain more numerous than Red-tailed Hawks on most of our tracts.

Figure 1. Number of Red-shouldered Hawks counted along Opinicon Road during the Red-shouldered Hawk and Spring Woodpecker Survey (1991-2010). There is a significant increase in the number of hawks counted between 1991 and 2010 (P=0.0013).

Literature Cited

1. Cadman, M.D., Sutherland, D.A., Beck, G.G., Lepage, D. and Couturier, A.R. (editors). 2007. Atlas of the Breeding Birds of Ontario, 2001-2005. Bird Studies Canada, Environment Canada, Ontario Field Ornithologists, Ontario Ministry of Natural Resources and Ontario Nature.
2. Weir, R.D. 2008. Birds of the Kingston Region 2nd edition, Quarry Press, Kingston.

Observations; Below the Surface, Round Lake, QUBS lands

Posted by: Shirley French

Daphnia pulicaria

For August and September, 2010, I helped a student, Amy McMullin, conduct experiments in the ‘field’ at Round Lake.  We measured the physical parameters (i.e. temperature, oxygen, light), sampled the zooplankton and ran experiments with live critters (Daphnia) in bottles at different depths.  Our study species was D. pulicaria (a water flea, left figure), a key component in many lake food webs where they consume tiny plants, the phytoplankton, and in turn, Daphnia are food for insect larvae (such as the Phantom midge) and for larval or juvenile fish.  The top predator at Round Lake seemed to be a pair of loons residing at the lake over the summer and their single offspring (young with their mother, below right).

Loon mother with baby.

Round Lake is appropriately named for its circular shape. The steep sides plunge down to a maximum depth of 30 meters.  The more gradual shore on the SE side is where we launch the boat.  One of the interesting features of this lake is the low oxygen in the bottom waters (i.e. 0.26 -0.10 mg/L from 15 m & below, Aug. 31/10).  As we were setting out and retrieving the Daphnia from jars in the water at 15 and 20 meters, I kept finding lovely dark pinkish-red clusters of cells in the water from the 20 m depth (Amy worked on the 15 m samples).  At first I wondered why there were red algae at a depth of 20 meters since we had measured the amount of light and it was extremely low!  I realized that it was not an algae after seeing an article on ‘Bahamas Blue Holes’ in National Geographic (August, 2010).   The articles’ description of diving through a zone of pink stained water (a layer of purple sulfur bacteria), made a strong impression.  As it turned out, the purple sulfur bacteria are inhabitants of freshwater environments as well as saltwater.  After examining some of the pinkish-red stuff under the microscope, the cells were easily identified as the purple sulfur bacteria, Amoebobacter (Pfennig and Trüper, 1989).  Even though the individual round cells are only 2-3 microns across, the colony is held together by wispy strands of mucus and so the bacteria are very easy to see with your eye.

What do the purple sulfur bacteria need to persist?  Like plants, they photosynthesize, but they use bacteriochlorophyll and carotenoids to capture light energy at wavelengths quite different from the ones used by algae (Pfennig and Trüper, 1989).  In addition, the purple sulfurs can photosynthesize at light levels 500 times lower than that available in the water’s surface layers on a sunny summer’s day. They are not as efficient at photosynthesis as the phytoplankton but they also grow in darkness and can adjust their buoyancy depending on their needs (Overmann and Pfennig, 1992).   In summary, the purple sulfur bacteria need sulfide compounds, have species specific ranges in temperature, need low oxygen or no oxygen for growth, and, have a wide range of salinity tolerances.  As mentioned, purple sulfurs grow in high salinity as in the Bahamas, salty lakes (Mahoney Lake, B.C.), or, in fresher water such as Round Lake.  Not surprisingly, the purple sulfur bacteria are thought to have arisen a long time ago (1.6 billion years before present; see Brocks and Schaeffer, 2008) when there was not a lot of oxygen in the oceans and the cyanobacteria were just getting started. Daphnia, on the other hand, have been around since “at least the Permian” (299 – 251 million years ago; Taylor et al., 1999).

Daphnia pulicaria. Actual size is ~2 mm (for adult females). Click on image for larger version.

In Round Lake Daphnia pulicaria are found throughout the water column. Some individuals are found in the low oxygen water, why are they there at all?  We noticed that some live specimens have an obvious red coloration that has been noted by other researchers and studied in Daphnia.   Like their predator found in Round Lake, the phantom midge Chaoborus flavicans, Daphnia produces hemoglobin in their bodies when they have been under low oxygen stress. It is their interesting adaptative plasticity and their suitability for lab experiments, which make Daphnia a good organism for studying energy budgets in Bill Nelson’s lab at Queen’s.

There are many unanswered questions about the plankton community and the physical features of Round Lake.  I had hoped to determine whether the lake had ‘turned over’ in the fall (i.e. early December), as is characteristic of many lakes, so it was necessary to sample the lake in the winter.  The weather was finally favorable Feb. 24th , the depth of the snow had shrunk and the air temperature was close to 0◦C.  The ATV didn’t make it very far on the trail and so I want to mention that my son, Linden’s, effort in dragging most of the sampling equipment to the lake and back was greatly appreciated.  Mark Conboy (Operations Manager at the Biological Station) had loaned us an ice auger and axe to cut a hole in the ice which was ~18 inches thick as Mark had said to expect.  Much to my excitement the temperature of the water in Round Lake was warmest in the bottom 20 to 29 meters.  The oxygen also abruptly changed from >3 mg/L in the upper 19 meters; to a low range of 0.56 – 0.43 mg/L in the bottom 9 meters.  The temperature profile indicated that the ‘densest’ (4◦C ) cool water in the upper layers, did not mix with the bottom waters (max. 4.7◦C); maintaining the low oxygen environment for the bacterial community.   It also suggests that the nutrients at the deep depths are not completely brought back into the water column with a fall or spring ‘turn over’ depriving the phytoplankton of a high nutrient supply.  The zooplankton appeared healthy, plump and many were red with hemoglobin in the February samples.

References

1. Brocks, J.J., and Schaeffer, P., 2008.  Okenane, a biomarker for purple sulfur bacteria (Chromatiacea) and other new carotenoid derivatives from the 1640 Ma Barney Creek Formation. Geochima et Cosmochimica Acta 72:  1396-1414.
2. Overmann, J. and Pfennig, N. 1992. Buoyancy regulation and aggregate formation in Amoebobacter purpureus from Mahoney Lake. Microbiology Ecology 101:  67-79.
3. Pfennig,N.  and Trüper,H.G.  1989.  Anoxygenic phototrophic bacteria.  In: Bergey’s manual of systematic bacteriology, Vol 3 (Staley, J.T., Bryant, M.P., Pfennig,N. and Holt, J.G. Eds.) pp.1635-1709. Williams and Wilkins, Baltimore,M.D.
4. Taylor, D.J., Crease,T.J. and Brown, W.M.  1999.  Phylogenetic evidence for a single long-lived clade of crustacean cyclic parthenogens and its implications for the evolution of sex. Proc. R. Soc. London B, 266:  791-797.

Hornemann’s Hoary Redpoll

Posted by Mark Andrew Conboy

It’s no secret that QUBS is a great place for birds and birders alike. Enthusiastic birders visit Opinicon Road every spring to search for species that are at the northern edge of their breeding ranges such as Yellow-billed Cuckoo (Coccyzus americanus), Red-bellied Woodpecker (Melanerpes carolinus), Blue-gray Gnatcatcher (Polioptila caerulea), Yellow-throated Vireo (Vireo flavifrons),

A female Hornemann’s Hoary Redpoll (right) and a female Southern Common Redpoll (left) at Ironwood Cottage on February 9, 2011. Some of the key field marks are visible in this photo: generally whiter plumage (compared to the Common Redpoll), diffuse streaking on sides, nearly immaculate undertail coverts and a robust head and neck. Photo: Philina English. Please click on photo for larger version

Golden-winged Warbler (Vermivora chrysoptera), Prairie Warbler (Dendroica discolor), Cerulean Warbler (D. cerulea), and Louisiana Waterthrush (Parkesia motacilla). QUBS has also been a hub of avian research for decades, especially for species like Tree Swallow (Tachycineta bicolor), Black-capped Chickadee (Poecile atricapillus), Golden-winged Warbler, Yellow Warbler (D. petechia), Cerulean Warbler, American Redstart (Setophaga ruticilla) and Red-winged Blackbird (Agelaius phoeniceus).
Though the breeding season provides the best birding and is the busiest research season, occasionally interesting and unusual birds show up at QUBS in the winter. This year we’ve had our fair share of notable species including an unseasonable Winter Wren (Troglodytes hiemalis) and a juvenile Golden Eagle (Aquila chrysaetos). But the bird that has attracted the most attention is a Hornemann’s Hoary Redpoll (Carduelis h. hornemanni) which has been visiting bird feeders at QUBS Point on an almost daily basis since February 9, 2011. This 14 g songbird has brought birders from as far away as Pennsylvania, Connecticut, Washington DC and New Jersey. To understand why a Hornemann’s Hoary Redpoll should be so popular among birders it’s necessary to know a thing or two about redpoll taxonomy and natural history.

Redpolls are small finches that breed in the high arctic and subarctic and spend the winter mainly south of the tundra throughout North America and Eurasia. There are two species redpolls in North America, both of which breed in low numbers in northern Ontario and winter in southern Ontario in most years. Redpolls are irruptive during the non-breeding season, which means that in some winters there are lots of redpolls and other winters there are few or none in Eastern Ontario. Annual fluctuations in redpoll numbers are usually correlated with fluctuations in the abundance of food sources, typically birch (Betula spp.) seeds. When seed crops are poor in the boreal forest, redpolls wander south in search of other foods including fodder from birdfeeders.

Whenever redpolls are present, Common Redpoll (C. flammea) is the most abundant species, while Hoary Redpolls (C. hornemanni) are far rarer, so they attract quite a lot of attention from birders when they appear. Both of the redpoll species are comprised of two subspecies (in North America). There is the Southern Common Redpoll (C. f. flammea) and the Greater Common Redpoll (C. f. rostrata); and there is the Southern Hoary Redpoll (C. h. exilipes) and Hornemann’s Hoary Redpoll (there are a wide variety of English names applied to each of these subspecies so it pays to know the scientific names too). The Southern Common and Southern Hoary Redpolls breed across the southern Canadian arctic and subarctic. Greater Common and Hornemann’s Hoary Redpolls breed further north, on Baffin Island, Greenland and in the case of Hornemann’s up to Ellesmere Island! Of the four subspecies, Hornemann’s is certainly the rarest in Ontario. It is only reported in some winters, particularly when there are large irruptions of redpolls.

It’s not uncommon to find both species of redpolls in the same flock, and sometimes three or even all four subspecies can be found together. This winter we’ve recorded all four of the redpoll subspecies at QUBS. Southern Common Redpolls are by far the most numerous with flocks sometimes in excess of 100 birds. Greater Common Redpolls and Southern Hoary Redpolls are seen singly or in pairs within these large flocks. The single female Hornemann’s Hoary Redpoll always appears with other redpolls where it can be easily recognized by comparison with other birds. Compared to the others the Hornemann’s Hoary Redpoll has whiter plumage, less streaking on sides, nearly all-white undertail coverts, more robust head and neck, smaller beak and is noticeably larger.
Its rarity, its size and its extreme northern breeding habitat make Hornemann’s Hoary Redpoll an attractive target for birders, hence the many visitors we’ve received at QUBS in the past two weeks. Redpoll identification can be difficult; in fact it is one of the most challenging identification problems birders face. Direct comparisons between individuals can be helpful and it is necessary to clearly see all field marks in order to properly diagnose which species or subspecies a redpoll belongs to. A good summary of redpoll identification by Ron Pittaway can be found at http://www.jeaniron.ca/2007/Redpolls/redpolltext3.htm.