Pacific Black Duck….or Not?

For more in depth info head over to eBird Australia

Identifying Mallard x Pacific Black Duck Hybrids


The Pacific Black Duck (Anas superciliosa), in the Family Anatidae, is one of the most common native dabbling Ducks. It can be found all across Australia, typically in association with water sources, i.e. ponds, lakes, rivers, wetlands, and is frequently seen in urban waterways.

The Mallard (Anas platyrhynchos) was introduced to Australia in the 1860s and has been spreading slowly across the south east and other populated areas.

These closely related species have similar habits and occupy the same environments. Where they are both present, the Mallards will breed with the local Pacific Black Ducks. With several broods each year of 7 to 12 ducklings, and 20% reaching adulthood, the Mallard genes quickly make their way into the local Pacific Black Duck population.



The New Zealand population of Pacific Black Ducks, locally known as Grey Ducks, is generally considered to be so extensively hybridized with Mallards, that the pure Grey Duck is considered exceptionally rare, bordering on extinct.

So when you spot what appears to be a Pacific Black Duck, how can you tell if it is actually a hybrid with Mallard genes? Being able to identify which are hybrids is a great skill to have. In urban areas you’ll quickly discover just how far ranging this issue already is, and you can help to spread awareness.

First up are the hybrids that have very distinct and obvious traits. Even to the untrained eye, the first impression will be that something ain’t right.



The easiest hybrid trait to recognise is the colour of the legs and feet. Mallards have bright orange legs, whereas PBDs have typically grey/green, dusky brown or tan. Hybrids can have legs bright orange like the Mallards. Some will have a duller orange. In photographs, lighting conditions can affect how orange the legs look. In dim light they can look darker. In early or evening warm sunlight, they can look more orange than usual.



A patchy bill is also quite easy to recognise, assuming you can get close enough to see. A pure PBD will have an evenly coloured grey/green bill. A hybrid may have an orange, yellow, or green bill often with patches.



Hybrids may also show lighter feathers and/or feathers with broad buff fringes. A pure PBD will have narrow buff fringes. This trait is a little more difficult to identify, in that it requires some observation experience of both PBDs and hybrids. This can be difficult in urban areas where many are hybrids showing varying degrees of this trait. (Also note below the ducklings show hybrid traits with varying facial markings).



There are several features on the head that may indicate a hybrid. A pure PBD will have a dark stripe from the gape to below the eye. (This stripe is not quite as dark/solid as the stripe through the eye). Hybrids may have this stripe entirely missing, a faint or wider stripe, or partial stripe that doesn’t extend the full distance. Additionally the crown of a PBD is typically quite dark. A streaked or paler crown may suggest a hybrid, however this may also be present on juveniles.



The final few visible traits that may be present in hybrids are a little more difficult to spot. In part because they are a matter of ‘degree’ where observation experience is necessary, or they are only visible in certain circumstances.

The coloured patch (speculum) on the wing of a pure PBD is iridescent green, bordered fore and aft by black. A hybrid may have an iridescent blue patch, however seeing this will depend on lighting angle. A hybrid may also show a white fore and aft trim, reminiscent of the Mallard which has a wide white trim.

Finally, the hybrids may show streaking / mottling extending up into the cream face patches and the tail feathers may be curled, as is typical of the Mallard.



Additionally, there are a sometimes atypical combinations of traits that indicate hybridisation, possibly with one of the domestic varieties of Mallard.



Further to the above, there is no guarantee that a hybrid will show any obvious visible traits. In urban areas where Mallards have been present for some time, it’s possible that all the local Pacific Black Ducks now have some Mallard ancestry.

There are a couple of other feral ducks that you may spot, particularly in urban areas. There are a few varieties of domestic Mallards that come in a range of colours. In fewer numbers, feral domestic Muscovy ducks (Cairina moschata) may be seen. These are quite easy to identify with their red warty faces.



To give some idea of the scale of the hybrid issue, almost all the above images have been recorded in the metropolitan areas in South Australia.

Considering all the above, let’s revisit the first photo in this post. Now how many pure Pacific Black Ducks can you see? Knowledge is the key to seeing the issue that’s been right in front of us the whole time.

If you’d like to help slow the spread of hybridisation, you can start by spreading the knowledge. Photograph any potential hybrids or feral Mallards you see and upload the images to iNaturalist. These records are synced with the Atlas of Living Australia and become records that can be utilised by scientists for research.



Below are a few links to further images, records and information on the issue of Pacific Black Duck x Mallard hybrids.

All iNaturalist records across South Australia for PBD x Mallard hybrids. Review the records and see if you can spot the hybrid traits. Some of the records have explanations in the comments.

All iNaturalist records across South Australia for pure Pacific Black Ducks. It’s worth noting that many of these records may yet be shown to be hybrids. See if you can spot any that might need correcting.

Mallards & hybrids in Australia iNaturalist Project, pooling over 3,000 records of feral Mallards and hybrids across Australia.

Mallard and Hybrid Ducks in Tasmania Facebook group. A wealth of information on hybrids.


Identifying the Thornbills of South Australia


Australian Thornbills (Genus Acanthiza) are notoriously difficult to identify. Difficult in the field and more difficult from photos alone. The tips below are a good starting point toward learning to ID the Thornbill species present in SA.


The Family Acanthizidae has 41 species across Australia with around 24 present in SA. The Genus Acanthiza includes 12 species across Australia with 9 of those occurring in SA.



Below are a few tips to help separate and identify these 9 species, with links through to the observations from SA so you can see what the distinguishing features look like in a variety of image qualities. The list is ordered based on the number of iNat observations. Those higher on the list are more frequently seen, likely due to their presence in more populated areas. Additionally those with the most distinct characteristics are more likely to be IDed to species level, so are higher on the list.




Acanthiza chrysorrhoa (Yellow-rumped Thornbill)
Birdlife Australia species page
eBird species page

Distinguishing Features: The bright yellow rump is sufficient alone to distinguish this species from others in SA. But this may not be visible if the Bird is facing the camera. In that case look for the black forehead with white spots, and dark eye stripe. In the right light, the grey/brown of the eye is visible. Most easily confused with Acanthiza reguloides (Buff-rumped Thornbill) which has a buff forehead and clear white eye.ID practice: Review the observations from SA and look for these features in the photos.



Acanthiza lineata (Striated Thornbill)
Birdlife Australia species page
eBird species page

Distinguishing Features: Look for the chestnut crown with white streaks. Heavy streaking on the chin, throat and chest. In the right light, the grey/brown of the eye is visible. Most easily confused with Acanthiza pusilla (Brown Thornbill), which has a reddish-brown forehead scalloped with paler markings and red eye.

ID practice: Review the observations from SA and look for these features in the photos.


Acanthiza pusilla (Brown Thornbill)
Birdlife Australia species page
eBird species page

Distinguishing Features: Reddish-brown forehead scalloped with paler markings. Rufous brown rump. Narrow black band on tail feathers. In the right light, the red brown of the eye is visible. Most easily confused with Acanthiza apicalis (Inland Thornbill), which has black and white scalloping on the forehead a wider black tail feather band, and Acanthiza lineata (Striated Thornbill), which has a chestnut crown with white streaks.

ID practice: Review the observations from SA and look for these features in the photos.


Acanthiza uropygialis (Chestnut-rumped Thornbill)
eBird species page

Distinguishing Features: Strong chestnut rump. Grey cream underparts without streaking. Buff forehead. In the right light, the clear white of the eye is visible. Most easily confused with Acanthiza apicalis (Inland Thornbill), which has streaking on the throat and chest.

ID practice: Review the observations from SA and look for these features in the photos.


Acanthiza nana (Yellow Thornbill)
Birdlife Australia species page
eBird species page

Distinguishing Features: The most yellow of the local Thornbills, with pale yellow underparts and white streaking restricted to the cheeks and ears. In the right light, the dark brown of the eye is visible. Most easily confused with Acanthiza lineata (Striated Thornbill), which has a chestnut crown with white streak, and heavily streaked chin, throat and chest.

ID practice: Review the observations from SA and look for these features in the photos.


Acanthiza reguloides (Buff-rumped Thornbill)
Birdlife Australia species page
eBird species page

Distinguishing Features: Buff-coloured rump and black tail. Buff-coloured forehead with cream-coloured scalloping. Off-white chin and chest without streaking. In the right light, the clear white of the eye is visible. Most easily confused with Acanthiza chrysorrhoa (Yellow-rumped Thornbill), which has a bright yellow rump and black forehead with white spots.

ID practice: Review the observations from SA and look for these features in the photos.


Acanthiza apicalis (Inland Thornbill)
eBird species page

Distinguishing Features: Black and white scalloping on the forehead, streaking on the throat and chest. Wide black band on the tail feathers. In the right light, the red of the eye is visible.
Most easily confused with Acanthiza pusilla (Brown Thornbill), which has a reddish-brown forehead scalloped with paler markings and a narrow black band on the tail feathers.

ID practice: Review the observations from SA and look for these features in the photos.


Acanthiza iredalei (Slender-billed Thornbill)
eBird species page

Distinguishing Features: Pale buff rump with contrasting darker tail. Faint speckling on the chest. Pale speckled forehead and face. In the right light, the clear white of the eye is visible.

ID practice: Review the observations from SA and look for these features in the photos.


Acanthiza robustirostris (Slaty-backed Thornbill)
eBird species page

Distinguishing Features: Dark streaking on the forehead. Only present in far North-West SA. In the right light, the red of the eye is visible. Most easily confused with Acanthiza apicalis (Inland Thornbill), which has streaking on the chest and black and white scalloping on the forehead.

ID practice: No iNat observations from SA. Review the observations from around Australia and look for these features in the photos.


Can you use these tips to ID the four species in the image at the beginning of this post?


Carnivorous Plants of SA: Drosera – Photographing & Identifying

The Venus Fly Trap or perhaps a Pitcher-Plant might be the typical images conjured up when considering carnivorous plants. However there are over 500 species of carnivorous plants worldwide to choose from. If you keep an eye out during the cooler months in SA and you might find any of the 21 species of local carnivorous plants, including several that are endemic to SA.


In SA there are two Genera of carnivorous plants. The Sundews (Genus Drosera), which include over 190 species worldwide, with 13 of these present in SA, and the Bladderworts (Genus Utricularia), which include over 200 species worldwide with 8 of these present in SA.


Sundews are perennial herbaceous plants that grow as prostrate or upright rosettes with stalked mucilaginous glands covering their leaf surfaces that ensnare and digest Insects. They are commonly found in mineral poor soils and use the captured Insects to provide the nutrients the soils lack.


Bladderworts are carnivorous plants that grow in wet soils or aquatic environments. The Plants grow primarily underground producing stolons with attached ‘vacuum-driven bladder traps’ that draw in prey to provide them with nutrients that the soils lack. The flower is the only part of the Plant that is visible above the soil.


In SA there are also several Plant Genera that are considered ‘proto-carnivorous’. The Triggerplants (Genus Stylidium) and closely related Styleworts (Genus Levenhookia). These may have glandular trichomes on their sepals, leaves, flower parts, or scapes that can trap small Insects, but it is as yet uncertain as to the primary reason for this function. As such they are not included in the list below.


The section below presents each of the 13 local Sundew species and provides recommendations of how these should be photographed to ensure the necessary features are captured to allow for a species level ID.


Drosera species

If you wish to go straight to the source of the information, see the Droseraceae section of the 5th Edition of the Flora of South Australia. If you are unfamiliar with the Drosera species in SA, this provides an overview including drawings of the parts of the Plants and photos of each, which can help to provide an idea of what to look out for when searching for these. The descriptions for each species may suit those more familiar with botanical terminology. The key provided is primarily based on traits that, as luck would have it, are visible in photographs. This means provided the right set of photographs is taken, a species level ID is frequently possible.

Since publishing in 2011 the document above has been superseded in part by newer treatments of those species in the Peltata complex in the last few steps of the key (R. P. Gibson 2012 & Miguel F. de Salas 2018)


The order species are shown below is based on the number of iNat records of each, so more commonly seen species are earlier in the list.


Drosera whittakeri (Whittaker’s Sundew)

SeedsSA Species Page
iNaturalist Observations in SA

Recommended Photos: Whole plant from above, if flowering ensure leaves are visible.
Tips: Common in Southern Lofty and Fleurieu Peninsula. Leaves with wide ribbed petioles. Flowers produced after leaves. Multiple flowers may open at once. Quite variable even within a single population, with some showing similarities to D. schmutzii and D. aberrans.

Typical form: (1)
Local iNat discussions: (1) (2) (3) (4)
Variations, abnormalities, and extreme forms : (Long stems) (Frozen) (Feeding) (Glabrous morph) (Broad petals) (Robust) (Abnormal petals) (Glands only on margins) (Drosera aff. schmutzii)

Climbing Sundew (Drosera macrantha ssp. planchonii / Drosera planchonii)

SeedsSA Species Page
iNaturalist Observations in SA

Recommended Photos: Whole plant, close up of leaf lamina.
Tips: Trailing or climbing growth habit unlike other local Drosera, leaf lamina orbicular, white flowers. iNat naming convention follows Plants of the World Online, so within iNat this is Drosera planchonii.

Typical form: (1)
Local iNat discussions: (1) (2)

Drosera auriculata (Tall Sundew)

SeedsSA Species Page
iNaturalist Observations in SA

Recommended Photos: Whole plant from the side showing the upright form, close-up of the flowers, sepals and leaves.
Tips: May or may not form a rosette of leaves at ground level. Cannot ID from rosette alone. Glabrous sepals, leaf lamina crescent shaped, generally pink flowers.

Typical form: (1)
Local iNat discussions: (1) (2) (3) (4)

Drosera glanduligera (Scarlet Sundew)

SeedsSA Species Page
iNaturalist Observations in SA

Recommended Photos: Whole plant from above, if flowering ensure leaves are visible.
Tips: One of the smaller Drosera, distinct orange flower, rosette leaf lamina spathulate (whereas the similar D. pygmaea has orbicular lamina)

Typical form: (1)

Drosera gunniana

iNaturalist Observations in SA

Recommended Photos: Whole plant from the side showing the upright form, close-up of the flowers, sepals and leaves.
Tips: Similar to D. auriculata with leaf lamina crescent shaped but hairy sepals. A taller single stemmed version of D. hookeri.

Typical form: (1)
Local iNat discussions: (1) (2) (3) (4)

Drosera praefolia (Early Sundew)

SeedsSA Species Page
iNaturalist Observations in SA

Recommended Photos: Flowers, whole plant.
Tips: Flowers occur before any leaves, but doesn’t always flower. Look for finished flower stalks protruding from under the leaves. Similar to D. whittakeri but with narrower & smoother petioles.

Typical form: (1)
Local iNat discussions: (1)

Tiny Sundew (Drosera pygmaea)

SeedsSA Species Page
iNaturalist Observations in SA

Recommended Photos: Whole plant from above.
Tips: The smallest local species, no bigger than a thumbnail. Leaf lamina orbicular.

Typical form: (1)

Drosera hookeri (Hooker’s Sundew)

SeedsSA Species Page
iNaturalist Observations in SA

Recommended Photos: Whole plant from the side showing the upright form, close-up of the sepals and leaves.
Tips: Difficult to ID from leaf rosette alone. Upright growth typically multiple stems with ‘shrubby’ appearance, often more yellow than D. auriculata. Leaf lamina crescent shaped. Sepals hairy.

Typical form: (1)
Local iNat discussions: (1)

Drosera aberrans (Scented Sundew)

SeedsSA Species Page
iNaturalist Observations in SA

Recommended Photos: Whole plant from above and wider angle showing colony forming habit.
Tips: These can at times look like Drosera whittakeri where their distributions overlap. Keep an eye out for narrow petioles and clonal / stoloniferous colony forming habit.

Typical form: (1)
Local iNat discussions: (1) (2)

Drosera schmutzii (Schmutz’s Sundew)

SeedsSA Species Page
iNaturalist Observations in SA

Recommended Photos: Whole plant from above, if flowering ensure leaves are visible.
Tips: Kangaroo Island endemic. Similar to D. whittakeri but with narrow petioles and narrowly-spathulate leaves. Doesn’t form clonal colonies like D. aberrans (but can grow in groups).

Typical form: (1)
Local iNat discussions: (1)

Drosera binata (Forked Sundew)

SeedsSA Species Page
iNaturalist Observations in SA

Recommended Photos: Whole plant showing long dividing leaves.
Tips: Quite distinct form, similar to D. finlaysoniana but with leaves dividing, distributions do not overlap.

Typical form: (1)

Drosera peltata / Drosera gracilis

SeedsSA Species Page
iNaturalist Observations in SA

Recommended Photos: Whole plant from the side showing the upright form especially the upper sections, sepals and leaf lamina.
Tips: Similar to other tall varieties with leaf lamina crescent shaped. Differs from D. gunniana in that it has a tall leafless inflorescence and is frequently a reddish colour with contrasting green sepals. Uncertainty exists as to what degree D. gracilis differs from D. peltata and whether it is considered synonymous.

Typical form: (1)

Drosera finlaysoniana (Flycatcher)

SeedsSA Species Page
iNaturalist Observations in SA

Recommended Photos: Whole plant showing long leaf form.
Tips: Quite distinct form, mostly Northern SA, similar to D. binata but without dividing leaves, distributions do not overlap.

Typical form: (1)

Drosera stricticaulis (Erect Sundew)

SeedsSA Species Page
iNaturalist Observations in SA

Recommended Photos: Whole plant from the side showing the upright form, close-up of the flowers, sepals and leaves.
Tips: Similar to D. planchonii with orbicular leaf lamina, but with erect upright form and pink flowers, southern Eyre Peninsula only.

Typical form: (1)

While recording Sundews, don’t forget to keep an eye out for the tiny Sundew Bugs (Setocoris sp.) that traverse the Sundews without getting trapped!

(The above info is quite generalised and only applicable to observations made in SA. If you encounter any issues/errors, please let me know).



Native Orchids of South Australia – Identification Resources


There are more than 350 native Orchid species in South Australia. While some have distinct characteristics that make identifying them relatively easy (when flowering), others can be a lot more difficult. Below I’ve compiled some resources that should help to aid both the beginner and experienced enthusiast in identifing local Orchids.


Beginner
For the beginner “The Common Native Orchids of the Adelaide Hills” is a two-page poster detailing 30 species of native Orchid commonly found in the Adelaide Hills.

If you are after a bit more detail, the 2011 Heritage Bushcare publication “Start with the Leaves: A simple guide to common orchids and lilies of the Adelaide Hills” by Robert Lawrence, provides info on 50 common native Orchids (and others that may be mistaken for Orchids). This book is also applicable to Kangaroo Island, Northern Lofty and South-East SA.

Other books that may be of use, but aren’t specific to Orchids, are “It’s Blue With 5 Petals: Wildflowers of the Adelaide Region” and “Focus on Flora: Native Plants of the Adelaide Hills and Barossa”


Enthusiast
For the enthusiast looking to dig deeper, “Orchids of South Australia (R.J. Bates & J.Z Weber, 1990)” is a comprehensive publication covering all Orchids in SA as of 1990. However this list in now quite outdated, describing only around 140 species from the 350 or so now known. It is freely available through the Department for Environment and Water website (click the link above to download the PDF). It includes keys, species descriptions, distributions, flowering times, etc. It also includes a colour plate of each species.

More recently the Native Orchid Society of South Australia published a DVD of South Australia’s Native Orchids (R.J. Bates, 2011). The included PDF builds upon the previous version of “Orchids of South Australia”. The text doesn’t follow the format of a traditional “Flora” and is quite easy to read. It is available for purchase through “NOSSA” and can be borrowed from a public library.

For a wider perspective try A Complete Guide to Native Orchids of Australia (3rd Edition, 2020) by David L. Jones. It doesn’t get more comprehensive than this.


Online
The primary online resource is the “Native Orchid Society of South Australia” website. The site has a blog and numerous articles on all aspects of local Orchids.


Future
In 2017 the University of Adelaide received a sizable citizen science grant to develop the “Wild Orchid Watch” project to collect, record and share scientific information about native Orchids. A short introductory video was recently released summarising the project. The project includes the development of an app allowing citizen scientists to record and upload native Orchid sightings, planned for release in 2020. (The app will have some iNaturalist integration, but as yet I am unsure what form this will take)


Pterostylis or Linguella? Caladenia or Arachnorchis? Corybas or Corysanthes?
Attempts have been made in the past to split up some of the larger Orchid genera (i.e. Pterostylis, Caladenia and Corybas) resulting in inconsistent naming conventions. The NOSSA article “A Beginner’s Guide to South Australian Orchid Name Usage” provides some background and a list of the common synonyms. A full list of synonyms published in South Australia’s Native Orchids (R.J. Bates, 2011), can be found “HERE”. iNaturalist handles synonyms reasonably well, i.e. if you begin to ID an observation as Linguella it will adjust it to Pterostylis to match the taxon scheme in use by iNaturalist.


What Orchids can I expect to find?
Again, the NOSSA website has some valuable info. The article “When Do Orchids Flower?” shows the number of species that can be found in flower in any given month or region across SA. The associated article “Month by Month Flowering Times” provides a full list of Orchids that may be flowering in each month.


SA Orchid observations
There have been a total of 1,374 observations of Orchids uploaded in SA from 88 species. This month there has been 290 observations from 37 species. That leaves around 260 species of native Orchid that have no iNaturalist observations recorded in SA, with upwards of 235 of them flowering during October.

Just one more reason to head out and see what you can find this Spring.