Giant (Ambrosia trifida ) as a Food Source for Autumn Migrants and Winter Birds in the Grand River Basin

Kenneth W. Dance, Kevin S. Dance and Michael B. Dance

Introduction Subsequent literature research and dis - An intense interest in foods of birds in cussions with colleagues revealed the fol - southern Ontario has led us to prepare a lowing: series of papers over the last 25 years, • Giant Ragweed is a native with starting with Dance (1986). a widespread distribution across During research for one of these Canada and the ; papers, on the use of Black Alder ( Alnus • it favours riparian habitats, particu - glutinosa ) by birds in southern Ontario, larly where flooding and erosion have it was observed that the seeds of Giant occurred — this apparently facilitates Ragweed (Ambrosia trifida ), a prominent establishment of this annual plant woodland edge and field species, were from seed (Abul-Fatih and Bazzaz being consumed consistently by birds at 1979a, b); a study site in the Nith River floodplain, • Giant Ragweed is becoming an ag - Oxford County (Dance 2008). gressive, invasive in cropland in

148 Ontario Birds December 2012 Figure 1. Size and shape of Giant Ragweed seeds.

“Knowing what a bird eats is • Giant Ragweed was considered to pose only a minor threat as an invas - fundamental if not ive weed, to upland natural areas central to understanding the (White et al. 1993); mysteries of its survival” • the seeds of this plant have been known to have high nutritional value (Heinrich 2003) for millennia, as witnessed by native peoples cultivation and consumption the mid- U.S. and Asia (Ishikawa et of Giant Ragweed seeds in the Mis - al. 2003, Kong et al. 2007, Shutte sissippi basin 3000 to 5000 years ago 2007); (McCann 1999); • some colleagues (K. Parker pers. • Giant Ragweed is also of broad eco - comm. and W.G. Wilson pers. logical and economic interest since it comm.) think that it has become has recently been confirmed to be the more widespread in the Grand River first weed species in Ontario to be basin during the last two decades; resistant to Roundup () —

Volume 30 Number 3 149 a herbicide in widespread use to con - Other authors have reported Red- trol in soybean and corn fields breasted Nuthatch ( Sitta canadensis ) (Ontario Farmer 2010, 2011); and and Red-winged Blackbird ( Agelaius • from a wildlife perspective, the high phoen iceus ) foraging for arthropods on nutrient content of the seeds (Will - Giant Ragweed (Miller 1914, son and Harmeson 1973) is of value Fischer 1953). to migrating and wintering bird Martin et al . (1961) reported on the species. occurrence of ragweed seeds in bird stomachs sampled across the United The size and shape of Giant Rag - States. They did not differentiate be - weed seeds are shown in Figure 1. tween Giant Ragweed and Common When first observed by us at one Ragweed ( Ambrosia artemisiifolia ), study site in 2005, Giant Ragweed grew which is more widespread and abun - in small patches. Following a signifi - dant in Ontario (Montgomery and cant flood in April 2008 (one of the two Switzer 1967). There are also additional largest floods during the preceding 50 Ambrosia species within the United years [ Ayr News 2009, Water loo Region States which do not occur in Ontario. Record 2009, 2010]), we observed that The Martin et al. (1961) findings the Giant Ragweed patches were several indicate that in general are times larger in area during the growing consumed by a variety of chickadee and season of 2008, than they had been in titmouse, Emberizid, cardinal and ally 2005. Presumably the scouring, silt dep - and blackbird taxa. osition and attendant widespread seed Martin et al . (1961) also list rag - transport had created suitable condi - weed among the plant taxa that bear tions for a localized expansion of the their seeds high enough that they are Giant Ragweed population. This situa - not covered by snow, making it a taxon tion seemed to be ideal for document - that has seeds available as bird food dur - ing the nature of bird species’ use of the ing much of the winter. seeds and cover provided by the large The principal purpose of the present dense Giant Ragweed beds present fol - study was to document the relative mag - lowing the April 2008 flood. nitude of use by autumn migrants and Documentation of wild birds con - winter birds of a weedy herb which may suming Giant Ragweed seed in North increase in prominence in riparian habi - America is limited but includes: Black- tats in the future. A secondary purpose capped Chickadee ( Poecile atricapillus ), was to document, in a preliminary way, Tufted Titmouse ( Baeolophus bicolor), the use of Giant Ragweed by spring Northern Cardinal ( Cardinalis cardi - migrants and breeding birds at two nalis ) and Common Redpoll ( Acanthis Southern Ontario sites. flammea ) (Fox 1940, Shepherd 2007).

150 Ontario Birds December 2012 Methods Mos t observations were made in the Detailed notes were kept on the species, morning, shortly after dawn, when birds numbers, uses and behaviour of birds ob - were active. Over 90% of t he obser - served on or immediately adjacent to the vation dates were between 21 September plants and stands of Giant Ragweed. The and 21 March. observation period ranged between 5 Sep - Results tember 2005 and 30 December 2010. Ten bird species were observed consum - Specific use(s) by birds were observed ing Giant Ragweed seed with Black- during 91 trips. capped Chickadee and Nort hern More than 95% of the observations Car d inal being observed the most fre - were recorded in the Nith River valley, quently foraging on Giant Ragweed seeds Blandford-Blenheim Township, Oxford (Table 1). County, Ontario. Many observations We observed seven bird species for - (September 2005 to December 2008) aging on Giant Ragweed plants for were near the confluence of Wolverton arthropods (Table 2). More intensive obs- Creek (a coldwater stream) and the Nith ervation effort during bird migration sea - River (17T 538500E 4790100N NAD sons would undoubt edly have revealed 1983). Giant Ragweed stands line the additional species searching for arthro - banks of both Wolverton Creek and por - pods in the dense Giant Ragweed stands tions of the Nith River in this location. present in the riparian zone. The second principal location of observations was along the Nith Table 1. Bird species observed consuming River upstream and downstream Giant Ragweed seed. of the Silver Bridge, located on NUMBER OF DATES Blenheim Road, south of County WHEN SEED CONSUMPTION SPECIES WAS OBSERVED Road 29 in Bland ford-Blenheim Township, Oxford County (17T Downy Woodpecker ( Picoides pubescens) 14 539951E 4787789N NAD 1983). Black-capped Chickadee ( Poecile atricapillus) 49 The Nith River is a tributary of Tufted Titmouse ( Baeolophus bicolor) 1 the Grand River. Less frequently Song Sparrow ( Melospiza melodia) 6 observations were recorded in Cambridge, Ontario, near the White-throated Sparrow ( Zonotrichia albicollis) 1 mouth of the Speed River and its Dark-eyed Junco ( Junco hyemalis) 1 confluence with the Grand River. Northern Cardinal ( Cardinalis cardinalis) 24 The two principal study sites Red-winged Blackbird ( Agelaius phoeniceus) 18 are within the extreme northern Purple Finch ( Haemorhous purpureus) 2 tip of the Norfolk Sand Plain House Finch ( Haemorhous mexicanus) 1 (Chapman and Putnum 1973). Total # Observation Dates 91

Volume 30 Number 3 151 Twenty-four bird species which Wild Turkey ( Meleagris gallopavo) N(3) were observed making other use(s) of Giant Ragweed plants are shown in Killdeer ( Charadrius vociferus) C(1) Table 3. Many of these bird species Spotted Sandpiper ( Actitis macularius) C(1) benefited from the cover and perch Ruby-throated Hummingbird sites provided by Giant Ragweed. Since (Archilochus colubris) PO(1) Black-capped Chickadees fed on Giant Downy Woodpecker Ragweed seed so frequently, separate (Picoides pubescens) PE(4) observations of cover use and perching Tufted Titmouse by chickadees were not recorded. (Baeolophus bicolor) PE(2), C(1) Two species were found nesting in Winter Wren ( Troglodytes hiemalis) P(1) or under Giant Ragweed stands and American Robin two species appeared to consume the (Turdus migratorius) C(1), P(1) of this plant (Table 3). American Tree Sparrow (Spizella arborea) C(4) Table 2. Bird species observed foraging for arthropods on Giant Ragweed plants Chipping Sparrow (Spizella passerina) C(1) SPECIES NUMBER OF OBSERVATIONS Fox Sparrow ( Passerella iliaca) C(1) Golden-crowned Kinglet Song Sparrow (Regulus satrapa) 2 (Melospiza melodia) C(16), PE(22) Ruby-crowned Kinglet Swamp Sparrow (Regulus calendula) 2 (Melospiza georgiana) C(2), PE(2) Nashville Warbler White-throated Sparrow (Oreothlypis ruficapilla) 1 (Zonotrichia albicollis) C(4), PE(3) Yellow-rumped Warbler Dark-eyed Junco ( Junco hyemalis) C(6), PE(2) (Setophaga coronata) 1 Northern Cardinal Common Yellowthroat (Cardinalis cardinalis) C(6), PE(6) (Geothlypis trichas) 2 Indigo Bunting ( Passerina cyanea) PE(1), PO(1) Song Sparrow (Melospiza melodia) 1 Red-winged Blackbird (Agelaius phoeniceus ) C(5), PE(4), N(3) Red-winged Blackbird (Agelaius phoeniceus) 1 Common Crackle ( Quiscalus quiscula) C(2) Pine Siskin ( Spinus pinus) PE(2)

Table 3. Bird species showing other uses American Goldfinch ( Spinus tristis) C(3) of Giant Ragweed House Sparrow ( Passer domesticus ) PE(1) SPECIES OTHER USE S* Canada Goose ( Branta canadensis) C(1) * Number of observations: C – provision of cover, N – nest cover, PO – pollen consumption Mallard ( Anas platyrhynchos) C(2) and PE – perching

152 Ontario Birds December 2012 Discusssion months of 2010 had very little snow Four bird species were observed to and the Giant Ragweed seed crop had make considerable use of Giant Rag - not been knocked down by snow, ice or weed seeds as a food source: Downy floods. Woodpecker ( Picoides pubescens) , Black- Song Sparrows ( Melospiza melodia ) capped Chickadee, Northern Cardinal, were observed eating Giant Ragweed and Red-winged Blackbird. The latter seeds on six dates. The consumption of three species have been documented to these seeds by Song Sparrows is proba - utilize ragweed seeds previously in bly much higher than reflected in the North America (Martin et al. 1961, data since detectability of this activity Brewer 1963, Smith 1991, Ritchison is so difficult due to the dense cover 1997). We have found, however, no present in a Giant Ragweed stand. Be - previous reports in the literature of tween 30 December 2009 and 20 Downy Woodpecker feeding on Giant March 2010 there were nine dates on Ragweed. which Song Sparrows were observed in Woodpeckers are known to feed on the Giant Ragweed stands being stud - fruit, nuts and plant seeds. Although ied. On these dates, the Song Sparrows Red-bellied Woodpeckers ( Melanerpes were documented using the stand for carolinus ) and Hairy Woodpeckers ( Pi - cover and/or perching. Also, on 27 De - coides villosus ) were present in the study cember 2008, four Song Sparrows were area and both species are known to present together in a large Giant Rag - feed on plant seeds (Backhouse 2005), weed stand. neither of these species were observed The Tufted Titmouse is considered on Giant Ragweed plants, nor con - to be an occasional species in fall and suming the seeds. Red-bellied Wood - winter in Oxford County. This is de - peckers, in particular, were consistently fined as very few records, normally ab - present flying over the ragweed patches sent. As far as breeding status is in winter. concerned, Skevington et al . (2010) in - Flocks of up to 600 Red-winged dicated that there is no evidence of Blackbirds were observed feeding on breeding in Oxford County. Giant Ragweed seed during autumn The Tufted Titmouse overwinters migration, suggesting Giant Ragweed successfully in the study area during seeds can be valuable food for migrants mild winters, but can be locally extir - to regain their energy stores. It is note - pated by extreme weather events such worthy that a flock of between 7 and as spring season ice storms (K.W. 12 Red-winged Blackbirds were ob - Dance unpublished data). South of the served feeding on seeds or were seen im - Great Lakes, in its original range, mediately adjacent to Giant Ragweed Tufted Titmice have been observed con - stands on two winter dates: 16 January suming Giant Ragweed seeds (Shep - and 27 February 2010.The first three herd 2007).

Volume 30 Number 3 153 In the present study, we had two analysis, however, may underestimate dates on which a single Tufted Titmouse the use of Giant Ragweed by bird species was observed. On 5 November 2008, a such as Black-capped Chickadee and titmouse was observed perched on a Downy Woodpecker, which break Giant Ragweed plant, but when we ar - through and remove the seed coat and rived it moved away with a band of consume the seed in pieces. We doubt Black-capped Chickadees without seed that fragments of Giant Ragweed seed consumption being observed. On 13 would be identifiable to species in bird February 2010, a single Tufted Titmouse stomachs. was observed using Giant Ragweed for The data on birds foraging for perching, cover and foraging on its seeds. arthropods on Giant Ragweed plants We saw the titmouse opening a Giant (Table 2) should be considered prelimi - Ragweed seed on two occasions by nary since the level of observation effort pounding it with the beak while holding during peak migration periods was quite it on a Manitoba Maple ( Acer negundo ) low. We, however, did confirm seven branch. The Tufted Titmouse was part bird species foraging for arthropods on of a mixed flock using the Giant Rag - Giant Ragweed plants. The results do weed patch, which included Black- suggest that the abundant insect emer - capped Chickadees, Northern Cardinals gence from the Nith River could pro - and Song Sparrows. vide a rich source of arthropod food to Our observation of Tufted Titmouse be found by birds on Giant Ragweed feeding on Giant Ragweed seeds are not plants, as was the case on adjacent Black unexpected since this species feeds on Alder trees (Dance 2008). larger seeds, including acorns and beech A considerable variety of birds (24 nuts (Grubb 1998); furthermore, this species) was found to use Giant Rag - species is known to winter in river-bot - weed plants as perches, including tom habitats that provide protection singing perches, and as cover. Of inter - from severe weather (Dunn and Tes - est were observations of a Wild Turkey saglia-Hymes 1999). (Meleagris gallopava ) nest sheltered from When summarizing the importance above by dried Giant Ragweed stalks of Ambrosia to wildlife, Martin et al. and Red-winged Blackbirds carrying (1961) indicated that Common Rag - food into pure stands of Giant Ragweed. weed ( Ambrosia artemisiifolia ) was of We did not search for nests until winter, major consequence as wildlife food and so as not to disturb the breeding black - Giant Ragweed was of little value. The birds. In winter, we were not able to reasoning for this was that the seeds of find the nests. the latter are large and have a tough At close range, one of us clearly saw coat, so birds use it little. Martin et al. Indigo Buntings ( Passerina cyanea ) pluck (1961) relied on bird stomach content pollen from Giant Ragweed flower analysis to determine food use. Stomach heads. On a single date, one of us saw a

154 Ontario Birds December 2011 Figure 2. Height of Giant Ragweed ensures seeds remain available to birds in autumn (October 2008) (2a) and winter (24 January 2010) (2b) (red circles show locations of seed clusters).

2a

2b

Volume 30 Number 3 155 Ruby-throate d Hummingbird (Archi - increase. This assumes that the stalks re - lochus colubris ), which also appeared to main sound and are not weakened or pluck pollen from a Giant Ragweed broken down by combinations of nat - flower head. Illinois Wildflowers ural forces such as rain, snow, wind or (2008) has reported the Honey Bee river ice. The force of floodwater and (Apis mellifera ) gathering Giant Rag - ice shearing off Giant Ragweed plants weed pollen. can be seen within the red circle (Figure 3, 2 January 2009). Following this Seasonal Availability of flood, there were no ragweed seeds Ragweed Seeds available to birds from standing stalks In the autumn and winter, Giant Rag - for the remainder of the winter. The weed seeds are available to birds by stalks and seed heads (outlined in red) virtue of their location high above the are shown in comparison to one of the ground (Figure 2). The height of Giant junior authors (184 cm tall) standing in Ragweed plants relative to a 173 cm tall one of the primary study areas (Figure adult human is shown in Figure 2a 2b, 24 January 2010). Seeds on up - (October 2008). Most seeds (in red cir - right stalks remained available to birds cles) are located on the upper half of until at least 20 February 2010, since the Giant Ragweed plant. This makes there was little snow cover and floods the seeds potentially available to birds and ice movement had not sheared off well into the winter, as snow depth s Giant Ragweed plants.

Figure 3. Force of floodwater and ice on Giant Ragweed plants.

156 Ontario Birds December 2012 The seasonal availability of Giant important food source for spring season Ragweed seed on standing stalks de - migrants. We had spring season records pends on three primary factors: (1) re - of the following bird species feeding on silience of stalks relative to weather, Giant Ragweed seed on the ground or floods and ice, (2) depletion of the seed within tangles of fallen stalks: Black- crop as a result of consumption by seed capped Chickadee, Song Sparrow, predators and (3) numbers of seeds that Northern Cardinal and Red-winged fall out of the seed holding receptacles. Blackbird. Harrison et al. (2003) report that This “weed” species was observed to mice and ground beetles are predators provide bird food on dates between 13 of Giant Ragweed seed; furthermore September and 27 March; thus in some these authors found that in Ohio during years Giant Ragweed seeds are con - winter, 43% of the seeds are depredated sumed by wintering birds and both au - and that for the entire year the percent - tumn and spring migrants. age rises to 88% of seeds. In Ohio, ro - dents were the dominant predators of Nutritional Value of ragweed seeds during fall and winter. Although significant effort was not Giant Ragweed Seeds expended to determine the quantity of Local sources of food that are available seed remaining on standing Giant Rag - throughout the cool and cold seasons weed stalks in late winter, we did make are essential to small active birds. Many notes on this factor during three winters. species operate on extremely thin mar - On 20 March 2009, standing stalks had gins of metabolic safety and can starve no seeds. On 13 February 2010, some to death in hours if deprived of food or plants had only two or three seeds left. subjected to harsh weather that causes Despite this observation, flocks of 12 them to burn more metabolic “fuel” chickadees and 12 cardinals were feed - than they can quickly replace. Birds can - ing in ragweed stands on 20 February not afford to store heavy food materials 2010. On 29 January 2011, forty stand - within their bodies for long periods and ing Giant Ragweed plants were exam - usually need a constant supply of nu - ined and were found to have an average trients to sustain activity. of 1.3 good seeds and 4.1 hollow seeds Several publications were found left per plant. The literature reports the which contain information on the number of seeds produced by a Giant nutritional characteristics of Giant Rag - Ragweed plant to be 275 in Canada weed seeds. These publications i ndic - (Bassett and Crompton 1982) and 247 ated Giant Ragweed seeds as having high nutritional value; key nutritional per plant in Japan (Ishikawa et al. 2003). Unless the seeds are buried by sedi - information is summarized below: mentation, damaged by abrasion and • Seeds of Giant Ragweed contain mould or consumed by other seed pred - about 19% edible oil content (W.J. ators, Giant Ragweed seeds can be an Beal Botanical Garden 2007).

Volume 30 Number 3 157 • Giant Ragweed seeds contain more Cardinals was considered by weight, metabolized energy by weight than Giant Ragweed was predominant. They corn (University of Missouri 2008). also found that at cold temperatures Giant Ragweed seeds consist of 47% (0°C) cardinals chose seeds yielding calo - crude protein and 38% crude fat ries at high rates such as hemp ( Cannabis (Harrison et al. 2003). sativa ) and Giant Ragweed, over three • Although slightly more than eight other seed choices. sunflower ( Helianthus annus ) seeds In addition to the need for adequate weigh one gram, it takes 28 ragweed winter food sources for resident birds, seeds to attain this weight (Willson suitable food sources in feeding areas and Harmeson 1973)(Table 4). One spaced along migratory flyways are gram of ragweed seed contains 29% equally as important. If migrating birds more calories than does one gram of are forced to fly too far between stop - sunflower seed and the protein con - overs, they can become stressed and tent of ragweed kernels is more than starve (Proctor and Lynch 1993). twice that of sunflower (Willson and Large flocks of hungry Red-winged Harmeson 1973). Blackbirds are a frequently observed • Lipid percent in the kernel of rag - phenomenon in river valleys in late weed is 43% higher than that of sun - summer and autumn. Heinrich (2003) flower (Willson and Harmeson stated that flocks of Red-winged Black - 1973). bird functionally are like a giant vac - uum cleaner, consuming large quantities The data reported by Willson and of food. Red-winged Blackbird flocks Harmeson (1973) are of interest because were observed feeding in large numbers they compared the metabolic content (often 80 to 600 birds) at three different of Giant Ragweed seeds from Illinois Giant Ragweed patches located within with those of commercial sunflower the two principal study areas. Feeding seed, which is a main component of was observed on 18 dates, 14 dates being most bird seed mixes because of its high during autumn migration: 13 Septem - nutritional value. In feeding experi - ber to 23 October. Single dates of oc - ments, Willson and Harmeson (1973) currence in January and February were found that when the diet of Northern also recorded. Red-winged Blackbirds

Table 4. Nutritional Value of Giant Ragweed Compared with Sunflower. NO. SEEDS/ g CALORIES/ CAL/ g % PROTEIN % LIPID KERNEL KERNEL IN KERNEL IN KERNEL

Giant Ragweed 28 141.8 7355 34 42 Commercial Sunflower 8+ 368.0 5256 15 24

Source: Willson and Harmeson, 1973

158 Ontario Birds December 2012 can find Giant Ragweed populations Black-capped Chickadee along much of the length of their fall mi - Average winter flock size of Black- gration routes since this plant has been capped Chickadees at the Giant Rag - documented to be a dominant herb in weed stands was around 6.6 individuals, the riparian habitats used by birds be - with typical flocks ranging from 6 to 8 tween Ontario and the Rio Grande Val - members. Large flocks are considered ley (Baltosser 1986, Johnston 1942 and to comprise of 8 to 10 individuals Zimmerman and Tatschl 1975). (Smith 1991). Although the Nith River valley has Where there is an “unusually rich been observed to be an important au - food source” flock ranges may overlap tumn migration route for Blue Jays and the birds will mingle, forming what (Cyanocitta cristata ) (K.W. Dance, un - is called a “compound flock” (Smith published data), this species was not ob - 1991). Examples of unusually rich food served to consume Giant Ragweed seed, sources included deer carcasses and well- nor to perch or seek cover among the stocked bird feeders. stems of this plant. There were 11 selected dates when 10 or more chickadees were observed Winter Bird Populations feeding together, in a Giant Ragweed Sustained by Giant Ragweed patch (Table 5). The largest number was Much of the present paper is devoted to 26 chickadees, accurately counted, as a discussion of the variety of bird species they moved out of a Giant Ragweed which were observed making some use patch via a narrow vegetated corridor of Giant Ragweed. An additional ques - flanking the riverbank. tion is: how many individual birds are By Smith’s (1991) definition these placing some reliance on Giant Rag - would have been large flocks. On three weed as a winter food source? of the 11 dates, two smaller flocks were For many species ( e.g. Downy Wood- seen to combine in or around a Giant pecker, and sparrow species), we usu - Ragweed patch, to form what Smith ally observed only a few (less than five) (1991) has defined as a compound flock. individuals feeding among the It seems reasonable to conclude that the Giant Ragweed patches. There were Giant Ragweed stands can be consid - occasions, however, when we were able ered to be an unusually rich food source, to accurately count the number of indi - since large and compound Black-capped viduals of a particular bird species en - Chickadee flocks were observed to be as - tering or leaving a Giant Ragweed patch. sociated with the ragweed stands. The Our observations indicate that the data from two sites and three different Giant Ragweed patches can support con - winters, confirm the importance of siderable numbers of Black-capped Giant Ragweed seeds as food for win - Chickadee and Northern Cardinal tering Black-capped Chickadee flocks (Table 5). (Table 5).

Volume 30 Number 3 159 Table 5. Number of Black-capped Chickadee and Northern Cardinal in large flocks entering or leaving a patch where feeding on Giant Ragweed was observed* SPECIES NUMBER DATE COMMENTS OF INDIVIDUALS Black-capped Chickadee 10 18 November 2005 16 27 November 2005 also gleaning on willow trees, eating Black Alder seed 12 10 December 2005 10 12 February 2006 11 23 November 2008 10 5 December 2008 2 flocks noted together 10 24 January 2010 12 7 February 2010 2 flocks noted together 26 13 February 2010 12 20 February 2010 11 6 March 2010 two flocks: 7 + 4 Northern Cardinal 11 5 December 2008 11 28 November 2009 13 29 November 2009 11 12 December 2009 12 5 January 2010 12 10 January 2010 11 16 January 2010 10 30 January 2010 12 20 February 2010 * large flock defined as 10 or more individuals

Northern Cardinal flock maintenance depended to some There were nine dates during two dif - extent on the Giant Ragweed seed as a ferent winters that Northern Cardinal food source. flocks of as many as 10 to 13 individu - Osborne (1992) reports autumn/ als were recorded feeding in or imme - winter flock sizes ranged between four diately adjacent to Giant Ragweed and 60 in Texas. In Ontario, where tem - patches (Table 5). Smaller flocks were peratures are more extreme and wild observed on other dates and in areas food resources can be patchy due to away from the ragweed stands. Our snow cover, a flock of 60 Northern Car - data suggest that winter survival and dinals would be considered to be very

160 Ontario Birds December 2012 large. Brooman (1954) records that 35 These authors indicated that counts of Northern Cardinals were counted along two to three Northern Cardinals were a short stretch of the Thames River bank typical. On one date in one ravine, a within Elgin County on 1 January 1946. maximum count of nine Northern Car - Kelly et al . (1963) report that winter dinals was obtained. flocks of 20 to 55 Northern Cardinals Dunn and Tessaglia-Hymes (1999) were observed where food supply was confirm that flocks of 50 or more cardi - plentiful in the Detroit-Windsor area nals are expected only by feeder owners between the mid-1940s and 1950s. in the United States. The vast majority A search of inventory data from three of feeder owners see fewer than five at winter bird population studies (WBPS), once, with one or two cardinals being which the senior author and others have more typical. These authors reported on conducted in three urban natural areas counts at bird feeders throughout the located in York and Waterloo Regions, U.S. and Canada. reveals that typical winter flock sizes of Our observations of flocks contain - cardinals are often in the range of three ing 10 to 13 Northern Cardinals associ - to six individuals (Dance 1989, Dance ated with the Giant Ragweed patches at and Geddes 1993, Dance and Dance two sites along the Nith River, suggest MS). All three of these natural areas were the presence of a rich food source which close to bird feeders, which would have attracts relatively large numbers of over - provided supplemental food to the win - wintering cardinals. ter flocks of Northern Cardinals. Two Studies have shown that dispersing were at inland sites with no river corridor cardinals tend to follow river systems present, while the third included riparian (Dow 1994). It is therefore not unex - habitat of a small river, but there was no pected that relatively large flocks of Giant Ragweed present. cardinals would be found to be con - At Lakeside Park, located in the Re - centrated around abundant energy-rich gion of Waterloo, and where winter bird food sources in winter, within the ripar - data were collected routinely between ian areas where Giant Ragweed can be 1981 and 1993, average numbers of found. Northern Cardinals present in the 14.2 ha study area were in the range of three Summary to six. On 11 dates, however, between To some, Giant Ragweed may be an un - eight and 17 cardinals were counted. desirable invasive native weed in their This study area had up to 42 stocked gardens and croplands, but based on the bird feeders present around its perimeter observations of this study at natural sites (Dance and Geddes 1993). in floodplains, it appears that this species Smith et al. (1981) reported on provides several valuable functions par - WBPS results from seven Toronto ticularly to winter birds, but also for ravines (with plot sizes of 5 to 20 ha). spring and autumn migrants. Winter

Volume 30 Number 3 161 birds are typically concentrated around Dance during preparation of the manuscript. areas that provide shelter or food or both We appreciate the constructive editorial com - (as Giant Ragweed stands do). Based on ments of Karl Konze, Chris Risley and Chip our observations, birders should consider Weseloh. adding Giant Ragweed stands as pro - ductive areas to search when doing gen - Literature Cited eral birding in winter, leading naturalist Abul-Fatih, H.A . and F.A. Bazzaz . 1979a. The Biology of Ambrosia trifida L. I. Influ - club outings for winter birds or Christ - ence of species removal on the organization of mas Bird Counts. For land owners and the plant community. New Phytologist managers of riparian habitats, it is im - 83:813 – 816. portant to consider the nutritional value Abul-Fatih, H.A. and F.A. Bazzaz . 1979b. of Giant Ragweed seeds to the survival of The Biology of Ambrosia trifida L. II. birds and mammals during harsh winter Germination, emergence, growth and months. survival. New Phytologist 83:817 – 827. Flannery (2005) predicts that as the Ayr News . 2009. 2009 review for Ayr and climate warms, rainfall will increase. The area. Page 2, December 23, 2009. incidence of flooding is also predicted to Backhouse, F. 2005. Woodpeckers of North increase if the climate warms. It is ex - America. Firefly Books Ltd. Richmond Hill, pected that Giant Ragweed will benefit ON. 232 pp. from disturbances caused by more flood - Baltosser, W.H. 1986. Seasonal analysis of a Southwestern New Mexico riparian bird ing, since its seeds will be car ried farther community. Western Birds 17:115 – 131. upslope to be deposited in rich sediments Bassett, I.J. and C.W. Crompton . 1982. The left by the receding waters. It may be that biology of Canadian weeds: Ambrosia trifida riparian zone bird communities will ben - L. Canadian Journal of Plant Science efit from an expansion in the extent of 62:1002 – 1010. Giant Ragweed stands in the future. Brewer, B. 1963. Ecological and reproductive relationship of Black-capped and Carolina Chickadees. Auk 80:9-47. Acknowledgements Brooman, R.C. 1954. Birds of Elgin County. We thank John and Gail Balkwill for access to The Gilbert Press, St. Thomas. their property, one of the key study sites. Charles Cecile, Cheryl Hendrickson, Ken Chapman, L. J. and D.F. Putnam . 1973. Parker and William G. Wilson shared their The Physiography of Southern Ontario. knowledge of the distributional status of Second Edition. University of Toronto Press. Giant Ragweed in Southern Ontario. Charles Toronto, ON. 386 pp. Cecile was helpful with advice on the botani - Dance, K.W. 1986. Winter food of Northern cal literature. Ken Parker also provided infor - Cardinal, American Tree Sparrow and Pine mation on use of Giant Ragweed by native Grosbeak in Southern Ontario. Ontario Birds peoples. Rudy Fecteau and John MacDonald 4:33 – 35. provided information on Giant Ragweed Dance, K.W. 1989. Frequency of winter bird seeds at Ontario archaeological sites. We occurrence at an urban conservation area. gratefully acknowledge the work by Janet Ontario Birds 7:20 – 25.

162 Ontario Birds December 2012 Dance, K.W. and S. Geddes . 1993. A winter Johnston, V.R. 1942. Factors influencing bird feeder survey in central Canada. Birders local movements of woodland birds in Journal 2:50 – 53. winter. Wilson Bulletin 54:192 – 198. Dance, K.W. 2008. Use of Black Alder Kelly, A.H. , D.S. Middleton , W.P. Nickell (Alnus glutinosa ) by birds in Southern and The Detroit Audubon Society Bird Ontario. Ontario Birds 26:58 – 67. Survey Committee . 1963. Birds of the Dance, K.W. and K.S. Dance . MS. Compar - Detroit-Windsor Area, A Ten-Year Survey. ison of winter bird populations in a wooded Cranbrook Institute of Science. 119 pp. suburban park during study periods three Kong, C.-H. , P. Wang and X.-H. Xu . 2007. decades apart. Manuscript in preparation. Allelopathic interference of Ambrosia trifida Dow, D.D . 1994. The Northern Cardinal in with Wheat ( Triticum aestivum ). Agriculture, Southern Ontario. In M.K. McNicholl and Ecosystems & Environment 119: 416 – 420. J.L. Cranmer-Byng [Eds.]. Ornithology in Martin, A.C. , H.S. Zim and A.L. Nelson . Ontario. Special Publication No. 1, Ontario 1961. American Wildlife & Plants A Guide Field Ornithologists. Pgs 291 – 297. to Wildlife Food Habits. Dover Publications Dunn, E.H. and D.L. Tessaglia-Hymes . Inc. New York, NY. 500 pp. 1999. Birds at Your Feeder. W.W. Norton McCann, J.M. 1999. Before 1492 the mak - & Company. New York. 418 pp. ing of the Pre-Columbian landscape. Part II: Fischer, R.B. 1953. Winter feeding of the The vegetation, and implications for restora - Red-wing ( Agelaius phoeniceus ). Auk 70: tion for 2000 and beyond. Ecological 496 – 497. Restoration 17:107 – 119. Flannery, T . 2005. The Weather Makers. Miller, R.F. 1914. Red-bellied Nuthatch Harper Collins Publishers Ltd. Toronto, ON. (Sitta canadensis) feeding among weeds. 356 pp. Auk 31:253 – 254. Fox, A.C. 1940. New food habitat for Montgomery, F.H. and C.M. Switzer . 1967. Common Redpoll. Auk 57:118. Ontario Weeds. Ontario Department of Agriculture and Food Publication 505. Grubb, T.C. Jr. 1998. Tufted Titmouse. Toronto, ON. 141 pp. Stackpole Books. Mechanicsburg, PA. 88 pp. Ontario Farmer. 2010. Glyphosate resistance Harrison, S.K. , E.E. Regnier and J.T. confirmed in Ontario. Page B3. 6 April Schmoll . 2003. Post dispersal predation of 2010. giant ragweed ( Ambrosia trifida ) seed in no-tillage corn. Weed Science 51:955 – 964. Ontario Farmer. 2011. An unfriendly giant among weeds. Pages B2 and B3. 4 January Heinrich, B. 2003. Winter World: The 2011. Ingenuity of Animal Survival. Harper Collins Publishers. New York, NY. 357 pp. Osborne, J. 1992. The Cardinal. University of Texas Press. Austin, TX. 108 pp. Illinois Wildflowers . 2008. Giant Ragweed (Ambrosia trifida ). http://www.illinoiswild - Proctor, N.S. and P.J. Lynch . 1993. Manual flowers.info/weeds/plants/giant_ragweed.htm of Ornithology Avian Structure & Function. 340 pp. Ishikawa, S. , K. Takahashi and H. Yoshii . 2003. Distribution and growth and germina - Ritchison, G. 1997. Wild Bird Guides tion characteristics of an alien plant, Northern Cardinal. Stackpole Books. Ambrosia trifida L., along the middle stream Mechanicsburg, PA. 122 pp. of the Tone River, Central Japan. Japanese Journal of Conservation Ecology 8:11 – 24.

Volume 30 Number 3 163 Schutte. B.J . 2007. Biology and ecology of University of Missouri. 2008. Giant Rag - Ambrosia trifi da L. seedling eme rgence. weed, MP90 3 Q uail – Fri endly Pla nts of the Ph.D. T hesis . Ohio State Un ive rsity. 16 4 pp. Midwe st, MU Extens ion. http ://exten sion.

Shepherd, A.J. 2007. Web site showing missouri.edu/p/MP903-19#Giantragweed photos of birds on Giant Ragweed plants. Waterloo Region Record . 2009. Residents http://www.aubunique.com. Site visited told flood control solutions too costly. 7 Octob er 2007. Page B2 . 20 Feb ru ary 200 9. Skevingt on, J.H . , H ol dsworth, J.M. and Wa ter loo Region Re cord . 201 0. Warm, dry Parker, B.D. 20 10. C hecklist o f the Birds spring in the fo recast . P age B1. 17 Ap ril of O xford Coun ty. 2nd Edi tion, Ma y 20 10. 2010.

Woodstock Field N atu ralists’ C lub, O ntario. White, D.J. , E. Haber and C.K. Keddy . 16 pp. Av ailabl e a t http:// www.exec ulink. 1993. In vasive Pl ants of N atura l Habitats in com /~w fnc/Oxford_ Bird_Check list.pdf Can ada. Canadian Wi ldlife Service. Ottawa, Smith, P . , D. C. Knaub er , D. Ulst er , ON. 121 pp.

D. Banville , J. MacDonald , G.M. Fairfield Willson, M.F . and J.C. Harmeson . 1973. and D.E . Burton . 19 81. Wi nter bird Seed preferences and digestive efficiency of communi ties of select ed ar eas in Toro nto. Cardin als and So ng S parrows . Con dor American Bird s 35:4 1 – 44. 75:225 – 2 34. Smith, S.M. 1 991. T he B lack-cap ped C hick - W.J. Bea l Bota nical Gard en . 2 00 7. G iant adee Behavioral Ecology and Natural History. Ragweed Amb ros ia trifida . htt p://www.cpa. Comstock Publishing Associ at es. Ithaca, NY. m1su.e d u/beal/ research/r esearch_f rames.htm O 362 pp. Zimmerman, J.L. and J.L. Tatschl . 1975. Floodp lain bi rds of Weston B end, Missouri. WDilson Bul letin 87:196 – 206.

B KCenneth W . Dance , Falcon R idge Farm, RB.R. #1 Drumb o, O ntario, N0J 1G0 EF-mail: dancenv@s entex.net Birding • Nature • Optics • Books KAe vin S. D anc e , 6 8 Hohne r Aven ue, &DQDGD·V/DUJHVW6HOHFWLRQRI%LQRFXODUVDQG6FRSHV Koi tche ner, O n tario , N2H 2V4 $OODW'LVFRXQW3ULFHV B Michael B. Dance, 259 Stanley St., ‡6ZDURYVNLSSwarovskiwarovski O Kowa Ayr, Ontario, N0B 1E0 ‡.RZDKowa ‡Z3ZeisseHisQs WD[ N ‡/HLFDLLeicaeica ‡1LNRQVVortexortex H ‡6ZLIWPPentaxentax H ‡%XVKQHOOBBushnellushnell L Celestron ‡=HLVVCelestron Nikon ‡SteinerNikon SSteinerteiner Minox B ‡&HOHVWURQ MManfrottoanfrotto Eagle B ‡9RUWH[ )RU)$67 0DLO2UGHU'HOLYHU\RU4XRWH E VDOHV#SHOHHZLQJVFD ZZZSHOHHZLQJVFD

164 Ontario Birds December 2012