In recent decades, many organisms, especially those that are highly mobile, have been expanding their natural range in response to humankind’s modification of the ecosystem, and in a few cases, due to natural random events (storms, etc).
Here in the Western Cape of South Africa where I live, there have been a few notable examples of species (especially birds such as the Hadeda Ibis) that did not historically occur in the region, but have since expanded and become established from their original core range in the northern and eastern parts of the country.
We all know about exotic, invasive species; that’s not the intended topic here. Instead, I would like to hear about species which are native to your country that have increased in numbers and expanded into new areas.
For many of us, we can remember a time where these species were not present, but over the years started to notice these arrivals more and more, until they almost seemed to be everywhere! It’s quite the interesting experience.
In Hong Kong, Lexias pardalis (a species of butterfly) was quite a rare species and can be found only in select areas within the country. When it became a lifer for me back in April 2018, it was still rare and restricted, but fast forward several months, I see observations of that sp. blowing up on iNat, and now it is not an uncommon sight, and can be found all around the country now. So this is a recent change, and I’m not sure about historical records.
2015 - 3 observations (year of 1st record in iNat in Hong Kong)
2016 - 2
2017 - 9
2018 - 45
2019 - 377
2020 - 376
And becuase the majority of inatters are just casual ones I dont think the lack of observations in the previous years was due to people just not spotting it.
In the United States the nine-banded armadillo is moving north fairly quickly. Undocumented north of the Rio Grande in 1850, they have infrequently been seen - usually after being hit by vehicles - as far north as northern Indiana, though there is unlikely to be a breeding population this far north due to the winters still having some very cold days most years.
It’s an interesting story both ecologically and politically. Some range expansions in Canada have been ongoing for long times. The northern cardinal first showed up in Canada in 1901. It began showing up in Thunder Bay, on the north shore of Lake Superior around the end of the 20th Century and in recent years it has been sen further north than that, even showing up in Moosonee near James Bay. It’s a beautiful bird and people have welcomed it at their feeders.
The double-crested cormorant is native to North America and has undergone significant range expansion since the 1960s. Contributing factors to the expansion in the Laurentian Great Lakes basin have included the presence of abundant exotic fish species like alewife and rainbow smelt which are ideal prey and increased overwinter survivorship of young birds related to the presence of extensive aquaculture facilities in the overwintering range. There has been outrage over the spread of this species on the part of sport fishing interests who view it as a competitor and cottagers who don’t like large colonies of smelly birds as neighbours. People are upset that the colonies become denuded of vegetation. The uproar has been sufficiently loud that culls have been instituted, including in parks and protected areas.
Here it can be seen well on insects, many Orthoptera that were restricted to south and drier regions are getting more and more north. Lycosa singoriensis is found in new regions almost every year.
Not sure how it’s relevant to weather changes or it’s a problem of having bee keepers, but while on university practice we found male&female (separately) Metoecus paradoxus it is a parasitoid of bees, it wasn’t mentioned in USSR guide for the region, so it took me long time to I’d it (as female looks nothing like a typical beetle), I found that first entioning of it from the region Leningrad Oblast is from 1976. Yellow-legged Gull weren’t found in Crimean and Caucasian waters in the early 2000-s, now they’re the most common species of gulls. Isabelline Wheatear was first found in Crimea in 80-s, I saw it twice now in the same spot in different years.
Other North American birds on the expansion include Western Kingbird (moving slowly but steadily into Illinois and eastern Missouri), White-winged Dove, Black-bellied Whistling Duck, Fish Crow, Black Vulture, and Lesser Black-backed Gull. I can also think of a few plants, including Helenium amarum (Bitterweed) , Sesbania herbacea (Bigpod Sesbania) and Spiranthes ovalis, all three expanding their range in Illinois. Notably, many of these birds and plants are Southern/Southwestern species.
Just today, I observed an Pheucticus melanocephalus in my yard…way out of it’s normal range and the first record of the bird for my state on iNat. I have seen it at the feeder for about a week now but could not get a clear photo until today.
Coyotes and nine-banded armadillos have seen massive range extensions in the past hundred years. Black bears are also being seen more often in my county in central MS, which is a great change for a species that was extirpated from most of the state only a few decades ago, even if it is just males passing through.
Two intriguing examples in Ontario are the Common Raven and the Merlin. Both of these birds have been emblematic of the ‘north woods’. If you lived in southern Ontario and didn’t see a Merlin during the migration the alternative was to drive north of Lake Superior and look for them nesting in the spruce stands along the Trans Canada Highway. Now they nest regularly in the cities around the southern part of the province. Although ravens weren’t confined to the boreal forest up until a couple of decades ago they were rarely found south of the Precambrian Shield. For the last couple of decades there has been at least 2 pair nesting near the west end of Lake Ontario and more spread across the southern province to the east. As birds moving south they’re expansion would be hard to explain by climate change.
Do you know if it has been determined for Ravens in particular the birds in our area are in fact coming from north of us ? The species is pretty common south of us in the Appalachians, and east of us. I wonder if there is any possibility it is being driven by whatever is causing Fish Crows to push into the western edges of Lake Ontario from Atlantic coastal regions.
I had always understood ravens to have been native to areas of southern Ontario with rugged terrain (like escapment country) but heavily persecuted by settlers for all the same reasons that raptors were persecuted. It was one of the birds I missed when we moved from northern Ontario to Bruce County in the early 70s.
In Cape Town I remember being mystified by Jo’burg based cartoons.
What’s a hadeda?
Now I have a pair regularly patrolling my garden. They leave junior here for the day - lots of mulch to fossick thru.
Great-tailed Grackle and White-winged Dove are two species that have greatly expanded northward in my state (New Mexico) since maybe the 1990s. The dove is a year-round resident in north-central NM while in the desert country of Arizona, which is certainly milder climate in winter, it apparently is only a summer resident.
In southeastern Washington/northeastern Oregon, people would’ve thought you were crazy if you saw a Bewick’s Wren or Lesser Goldfinch 15 years ago. Now they’re one of the most common species coming to your feeders.
In Southern Ontario, especially in the southeast, Red-bellied Woodpecker has gone from a rare wanderer to a widespread feeder bird in the past 10 years. I’m really not sure how many of those birds are breeding but some are certainly nesting. Someone else mentioned Merlin in Ontario. I actually think that they peaked in our area about 20 years ago and are now less common although still much more widespread as a breeder than they were historically.
The new Ontario Breeding Bird Atlas starts in 2021 so we’ll be better positioned to answer the question about birds, at least, in a few years.
Regarding plants, one should raise the question: expanding or “being expanded”?
Here in recent years, some plants known to be native, or believed to be so, have expanded their range in three main ways:
Discontinuously: they have appeared many km away (mostly northwards) from where they have been seen before
Continuously: along the network of the communication routes
In proximity of where they have been employed in reforestations
These three ways of range expansion could suggest that the concept of native plant species is somehow misleading if treated on the basis of the administrative units such as regions or states. It is clear that a plant species can be both native and introduced in a certain administrative unit.
Here in northeast Ohio we have a growing population of Fish Crows, particularly in Cuyahoga County. In Lake County just east of here, a pair of Ravens set up house and have nested the last few years, presumably successfully. We also had a pair of White-winged Doves attempt to nest in Euclid, Ohio (Cuyahoga County) this year. Black Vultures have established themselves in northern Ohio now as well…they used to be limited to central Ohio and south.
@cmcheatle, @kenallison, Evidence that the Ravens are moving south is found in the results of the 2nd Ontario Breeding Bird Atlas. There was a near uniform expansion along the southern and eastern edge of their recorded range from the first atlas. Their first nesting in Hamilton was likely 2006 with 2 nesting pair confirmed in 2013. Many of the nestings were successful and the species is now regularly seen around the area. It’s interesting that Fish Crows are moving in from the south and Ravens from the north.
Nesting Merlin are certainly commoner now in Hamilton then they were a few years ago. The first nesting record was in 2010 and there have been multiple records since. Before this there are records of nesting in Cambridge and Brantford in 2008. This appears to be a continuation of the dramatic expansion shown between the 1st OBBA (1981-85) and the 2nd (2001-05).